Wireshark Lua: 一个从RTP抓包里导出H.264 Payload，变成264裸码流文件（xxx.264）的Wireshark插件

     抓取一个包含H.264 Payload RTP包的SIP会话或RTSP会话后，用Wireshark的Play功能只能播放声音，不能播放视频。把RTP payload直接导出成文件后也是不能直接播放的，因为H.264 over RTP封包是符合RFC3984规范的，必须按照该规范把H.264数据取出来后，组成NALU，放到avi/mp4或裸码流文件等容器里后才能播放。

     本人写了一个wireshark插件，可以在打开包含H.264码流的抓包后，选菜单“Tools->Export H264 to file [HQX's plugins]”后，把抓包文件里的H.264码流自动导出到抓包文件所在目录（工作目录）里，名为from_<RTP流源ip>_<RTP流源端口>_to_<RTP流目的ip>_<RTP流目的端口>.264的264裸码流文件里。（文件格式为每个NALU前加0x00000001分隔符）。

      本程序可以识别RFC3984里提到的三种H.264 over RTP封装，分别是Single NALU（一个RTP含一个NALU）、STAP-A（一个RTP包含多个NALU）、FU-A（一个NALU分布到多个RTP包）三种封装格式，且会自动把SPS和PPS放到裸码流文件头部。

Lua脚本如下：

-- Dump RTP h.264 payload to raw h.264 file (*.264)
-- According to RFC3984 to dissector H264 payload of RTP to NALU, and write it
-- to from<sourceIp_sourcePort>to<dstIp_dstPort>.264 file. By now, we support single NALU,
-- STAP-A and FU-A format RTP payload for H.264.
-- You can access this feature by menu "Tools->Export H264 to file [HQX's plugins]"
-- Author: Huang Qiangxiong ([email protected])
-- change log:
--      2012-03-13
--          Just can play
------------------------------------------------------------------------------------------------
do
    -- for geting h264 data (the field's value is type of ByteArray)
    local f_h264 = Field.new("h264") 

    -- menu action. When you click "Tools->Export H264 to file [HQX's plugins]" will run this function
    local function export_h264_to_file()
        -- window for showing information
        local tw = TextWindow.new("Export H264 to File Info Win")
        local pgtw = ProgDlg.new("Export H264 to File Process", "Dumping H264 data to file...")
        
        -- add message to information window
        function twappend(str)
            tw:append(str)
            tw:append("\n")
        end
        
        -- running first time for counting and finding sps+pps, second time for real saving
        local first_run = true 
        -- variable for storing rtp stream and dumping parameters
        local stream_infos = {}

        -- trigered by all h264 packats
        local my_h264_tap = Listener.new(tap, "h264")
        
        -- get rtp stream info by src and dst address
        function get_stream_info(pinfo)
            local key = "from_" .. tostring(pinfo.src) .. "_" .. tostring(pinfo.src_port) .. "to" .. tostring(pinfo.dst) .. "_" .. tostring(pinfo.dst_port)
            local stream_info = stream_infos[key]
            if not stream_info then -- if not exists, create one
                stream_info = { }
                stream_info.filename = key.. ".264"
                stream_info.file = io.open(stream_info.filename, "wb")
                stream_info.counter = 0 -- counting h264 total NALUs
                stream_info.counter2 = 0 -- for second time running
                stream_infos[key] = stream_info
                twappend("Ready to export H.264 data (RTP from " .. tostring(pinfo.src) .. ":" .. tostring(pinfo.src_port) 
                         .. " to " .. tostring(pinfo.dst) .. ":" .. tostring(pinfo.dst_port) .. " to file:\n         [" .. stream_info.filename .. "] ...\n")
            end
            return stream_info
        end
        
        -- write a NALU or part of NALU to file.
        function write_to_file(stream_info, str_bytes, begin_with_nalu_hdr)
            if first_run then
                stream_info.counter = stream_info.counter + 1
                
                if begin_with_nalu_hdr then
                    -- save SPS or PPS
                    local nalu_type = bit.band(str_bytes:byte(0,1), 0x1F)
                    if not stream_info.sps and nalu_type == 7 then
                        stream_info.sps = str_bytes
                    elseif not stream_info.pps and nalu_type == 8 then
                        stream_info.pps = str_bytes
                    end
                end
                
            else -- second time running
                if stream_info.counter2 == 0 then
                    -- write SPS and PPS to file header first
                    if stream_info.sps then
                        stream_info.file:write("\00\00\00\01")
                        stream_info.file:write(stream_info.sps)
                    else
                        twappend("Not found SPS for [" .. stream_info.filename .. "], it might not be played!\n")
                    end
                    if stream_info.pps then
                        stream_info.file:write("\00\00\00\01")
                        stream_info.file:write(stream_info.pps)
                    else
                        twappend("Not found PPS for [" .. stream_info.filename .. "], it might not be played!\n")
                    end
                end
            
                if begin_with_nalu_hdr then
                    -- *.264 raw file format seams that every nalu start with 0x00000001
                    stream_info.file:write("\00\00\00\01")
                end
                stream_info.file:write(str_bytes)
                stream_info.counter2 = stream_info.counter2 + 1
                
                if stream_info.counter2 == stream_info.counter then
                    stream_info.file:flush()
                    twappend("File [" .. stream_info.filename .. "] generated OK!\n")
                end
                -- update progress window's progress bar
                if stream_info.counter > 0 then pgtw:update(stream_info.counter2 / stream_info.counter) end
            end
        end
        
        -- read RFC3984 about single nalu/stap-a/fu-a H264 payload format of rtp
        -- single NALU: one rtp payload contains only NALU
        function process_single_nalu(stream_info, h264)
            write_to_file(stream_info, h264:tvb()():string(), true)
        end
        
        -- STAP-A: one rtp payload contains more than one NALUs
        function process_stap_a(stream_info, h264)
            local h264tvb = h264:tvb()
            local offset = 1
            repeat
                local size = h264tvb(offset,2):uint()
                write_to_file(stream_info, h264tvb(offset+2, size):string(), true)
                offset = offset + 2 + size
            until offset >= h264tvb:len()
        end
        
        -- FU-A: one rtp payload contains only one part of a NALU (might be begin, middle and end part of a NALU)
        function process_fu_a(stream_info, h264)
            local h264tvb = h264:tvb()
            local fu_idr = h264:get_index(0)
            local fu_hdr = h264:get_index(1)
            if bit.band(fu_hdr, 0x80) ~= 0 then
                -- start bit is set then save nalu header and body
                local nalu_hdr = bit.bor(bit.band(fu_idr, 0xE0), bit.band(fu_hdr, 0x1F))
                write_to_file(stream_info, string.char(nalu_hdr), true)
            else
                -- start bit not set, just write part of nalu body
            end
            write_to_file(stream_info, h264tvb(2):string(), false)
        end
        
        -- call this function if a packet contains h264 payload
        function my_h264_tap.packet(pinfo,tvb)
            local h264s = { f_h264() } -- using table because one packet may contains more than one RTP
            for i,h264_f in ipairs(h264s) do
                if h264_f.len < 2 then
                    return
                end
                local h264 = h264_f.value   -- is ByteArray
                local hdr_type = bit.band(h264:get_index(0), 0x1F)
                local stream_info = get_stream_info(pinfo)
                
                if hdr_type > 0 and hdr_type < 24 then
                    -- Single NALU
                    process_single_nalu(stream_info, h264)
                elseif hdr_type == 24 then
                    -- STAP-A Single-time aggregation
                    process_stap_a(stream_info, h264)
                elseif hdr_type == 28 then
                    -- FU-A
                    process_fu_a(stream_info, h264)
                else
                    twappend("Error: unknown type=" .. hdr_type .. " ; we only know 1-23(Single NALU),24(STAP-A),28(FU-A)!")
                end
            end
        end
        
        -- close all open files
        function close_all_files()
            if stream_infos then
                for id,stream in pairs(stream_infos) do
                    if stream and stream.file then
                        stream.file:close()
                        stream.file = nil
                    end
                end
            end
        end
        
        function my_h264_tap.reset()
            -- do nothing now
        end
        
        function remove()
            close_all_files()
            my_h264_tap:remove()
        end
        
        tw:set_atclose(remove)
        
        -- first time it runs for counting h.264 packets and finding SPS and PPS
        retap_packets()
        first_run = false
        -- second time it runs for saving h264 data to target file.
        retap_packets()
        -- close progress window
        pgtw:close()
    end
    
    -- Find this feature in menu "Tools->"Export H264 to file [HQX's plugins]""
    register_menu("Export H264 to file [HQX's plugins]", export_h264_to_file, MENU_TOOLS_UNSORTED)
end

把代码保存成h264_export.lua文件，放到wireshark安装目录下，然后修改wireshark安装目录下的init.lua文件：

（1）若有disable_lua = true这样的行，则注释掉；

（2）在文件末加入dofile("h264_export.lua")

重新打开wirekshark就能使用该功能了。

 

另外，264裸码流文件一般播放器不一定能播放，推荐使用ffmpeg的ffplay播放，或用ffmpeg转成通用文件格式播放。

 

2014年升级版，支持排序、丢弃不完整帧，注意生成的文件from...在抓拍文件相同的目录：

-- Dump RTP h.264 payload to raw h.264 file (*.264)
-- According to RFC3984 to dissector H264 payload of RTP to NALU, and write it
-- to from<sourceIp_sourcePort>to<dstIp_dstPort>.264 file. By now, we support single NALU,
-- STAP-A and FU-A format RTP payload for H.264.
-- You can access this feature by menu "Tools->Export H264 to file [HQX's plugins]"
-- Author: Huang Qiangxiong ([email protected])
-- change log:
--      2012-03-13
--          Just can play
--      2012-04-28
--          Add local to local function, and add [local bit = require("bit")] to prevent
--          bit recleared in previous file.
--      2013-07-11
--          Add sort RTP and drop uncompleted frame option.
--      2013-07-19
--          Do nothing when tap is triggered other than button event.
--          Add check for first or last packs lost of one frame.
------------------------------------------------------------------------------------------------
do
    local bit = require("bit")

    -- for geting h264 data (the field's value is type of ByteArray)
    local f_h264 = Field.new("h264") 
    local f_rtp = Field.new("rtp") 
    local f_rtp_seq = Field.new("rtp.seq")
    local f_rtp_timestamp = Field.new("rtp.timestamp")
    local nalu_type_list = {
        [0] = "Unspecified",
        [1] = "P/B_slice",
        [2] = "P/B_A",
        [3] = "P/B_B",
        [4] = "P/B_C",
        [5] = "I_slice",
        [6] = "SEI",
        [7] = "SPS",
        [8] = "PPS",
        [9] = "AUD",
    }
    
    local function get_enum_name(list, index)
        local value = list[index]
        return value and value or "Unknown"
    end

    -- menu action. When you click "Tools->Export H264 to file [HQX's plugins]" will run this function
    local function export_h264_to_file()
        -- window for showing information
        local tw = TextWindow.new("Export H264 to File Info Win")
        --local pgtw = ProgDlg.new("Export H264 to File Process", "Dumping H264 data to file...")
        local pgtw;
        
        -- add message to information window
        function twappend(str)
            tw:append(str)
            tw:append("\n")
        end
        
        -- running first time for counting and finding sps+pps, second time for real saving
        local first_run = true 
        -- variable for storing rtp stream and dumping parameters
        local stream_infos = nil
        -- drop_uncompleted_frame
        local drop_uncompleted_frame = false
        -- max frame buffer size
        local MAX_FRAME_NUM = 3

        -- trigered by all h264 packats
        local my_h264_tap = Listener.new(tap, "h264")
        
        -- get rtp stream info by src and dst address
        function get_stream_info(pinfo)
            local key = "from_" .. tostring(pinfo.src) .. "_" .. tostring(pinfo.src_port) .. "to" .. tostring(pinfo.dst) .. "_" .. tostring(pinfo.dst_port) .. (drop_uncompleted_frame and "_dropped" or "_all")
            local stream_info = stream_infos[key]
            if not stream_info then -- if not exists, create one
                stream_info = { }
                stream_info.filename = key.. ".264"
                stream_info.file = io.open(stream_info.filename, "wb")
                stream_info.counter = 0 -- counting h264 total NALUs
                stream_info.counter2 = 0 -- for second time running
                stream_infos[key] = stream_info
                twappend("Ready to export H.264 data (RTP from " .. tostring(pinfo.src) .. ":" .. tostring(pinfo.src_port) 
                         .. " to " .. tostring(pinfo.dst) .. ":" .. tostring(pinfo.dst_port) .. " to file:\n         [" .. stream_info.filename .. "] ...\n")
            end
            return stream_info
        end
        
        -- write a NALU or part of NALU to file.
        local function real_write_to_file(stream_info, str_bytes, begin_with_nalu_hdr)
            if first_run then
                stream_info.counter = stream_info.counter + 1
                
                if begin_with_nalu_hdr then
                    -- save SPS or PPS
                    local nalu_type = bit.band(str_bytes:byte(0,1), 0x1F)
                    if not stream_info.sps and nalu_type == 7 then
                        stream_info.sps = str_bytes
                    elseif not stream_info.pps and nalu_type == 8 then
                        stream_info.pps = str_bytes
                    end
                end
                
            else -- second time running
                --[[
                if begin_with_nalu_hdr then
                    -- drop AUD
                    local nalu_type = bit.band(str_bytes:byte(0,1), 0x1F)
                    if nalu_type == 9 then
                        return;
                    end
                end
                ]]
                
                if stream_info.counter2 == 0 then
                    -- write SPS and PPS to file header first
                    if stream_info.sps then
                        stream_info.file:write("\00\00\00\01")
                        stream_info.file:write(stream_info.sps)
                    else
                        twappend("Not found SPS for [" .. stream_info.filename .. "], it might not be played!\n")
                    end
                    if stream_info.pps then
                        stream_info.file:write("\00\00\00\01")
                        stream_info.file:write(stream_info.pps)
                    else
                        twappend("Not found PPS for [" .. stream_info.filename .. "], it might not be played!\n")
                    end
                end
            
                if begin_with_nalu_hdr then
                    -- *.264 raw file format seams that every nalu start with 0x00000001
                    stream_info.file:write("\00\00\00\01")
                end
                stream_info.file:write(str_bytes)
                stream_info.counter2 = stream_info.counter2 + 1

                -- update progress window's progress bar
                if stream_info.counter > 0 and stream_info.counter2 < stream_info.counter then pgtw:update(stream_info.counter2 / stream_info.counter) end
            end
        end
        
        local function comp_pack(p1, p2)
            if math.abs(p2.seq - p1.seq) < 1000 then
                return p1.seq < p2.seq
            else -- seqeunce is over 2^16, so the small one is much big
                return p1.seq > p2.seq
            end
        end
        
        local function print_seq_error(stream_info, str)
            if stream_info.seq_error_counter == nil then
                stream_info.seq_error_counter = 0
            end
            stream_info.seq_error_counter = stream_info.seq_error_counter + 1
            twappend(str .. " SeqErrCounts=" .. stream_info.seq_error_counter)
        end
        
        local function sort_and_write(stream_info, frame)
            table.sort(frame.packs, comp_pack)
            
            -- check if it is uncompleted frame
            local completed = true
            for i = 1, #frame.packs - 1, 1 do
                local seq1 = frame.packs[i].seq
                local seq2 = frame.packs[i+1].seq
                if bit.band(seq1+1, 0xFFFF) ~= seq2 then
                    print_seq_error(stream_info, " RTP pack Lost: timestamp=" .. frame.timestamp .. " seq between " .. seq1 .. " and " .. seq2)
                    completed = false
                end
            end
            
            if not frame.packs[1].nalu_begin then
                print_seq_error(stream_info, " RTP pack Lost: timestamp=" .. frame.timestamp .. " seq before " .. frame.packs[1].seq)
                completed = false
            end
            
            if not frame.packs[#frame.packs].nalu_end then
                print_seq_error(stream_info, " RTP pack Lost: timestamp=" .. frame.timestamp .. " seq after " .. frame.packs[#frame.packs].seq)
                completed = false
            end
            
            if completed then
                for i = 1, #frame.packs, 1 do
                    real_write_to_file(stream_info, frame.packs[i].data, frame.packs[i].nalu_begin)
                end
            else
                twappend("   We drop one uncompleted frame: rtp.timestamp=" .. frame.timestamp 
                         .. " nalu_type=" .. frame.nalu_type .."(" .. get_enum_name(nalu_type_list, frame.nalu_type) .. ")")
            end
        end
        
        local function write_to_file(stream_info, str_bytes, begin_with_nalu_hdr, timestamp, seq, end_of_nalu)
            if drop_uncompleted_frame and not first_run then -- sort and drop uncompleted frame
                if stream_info.frame_buffer_size == nil then
                    stream_info.frame_buffer_size = 0
                end
                
                if timestamp < 0 or seq < 0 then
                    twappend(" Invalid rtp timestamp (".. timestamp .. ") or seq (".. seq .. ")! We have to write it to file directly!")
                    real_write_to_file(stream_info, str_bytes, begin_with_nalu_hdr)
                    return;
                end
                
                -- check if this frame has existed
                local p = stream_info.frame_buffer
                while p do
                    if p.timestamp == timestamp then
                        break;
                    else
                        p = p.next
                    end
                end
                
                if p then  -- add this pack to frame
                    if begin_with_nalu_hdr then
                        p.nalu_type = bit.band(str_bytes:byte(1), 0x1F)
                    end
                    table.insert(p.packs, { ["seq"] = seq, ["data"] = str_bytes , ["nalu_begin"] = begin_with_nalu_hdr, ["nalu_end"] = end_of_nalu })
                    return
                end
                
                if stream_info.frame_buffer_size >= MAX_FRAME_NUM then
                    -- write the most early frame to file
                    sort_and_write(stream_info, stream_info.frame_buffer)
                    stream_info.frame_buffer = stream_info.frame_buffer.next
                    stream_info.frame_buffer_size = stream_info.frame_buffer_size - 1
                end
                
                -- create a new frame buffer for new frame (timestamp)
                local frame = {}
                frame.timestamp = timestamp
                if begin_with_nalu_hdr then
                    frame.nalu_type = bit.band(str_bytes:byte(1), 0x1F)
                end
                frame.packs = {{ ["seq"] = seq, ["data"] = str_bytes, ["nalu_begin"] = begin_with_nalu_hdr, ["nalu_end"] = end_of_nalu}}  -- put pack to index 1 pos
                frame.next = nil
                
                if stream_info.frame_buffer_size == 0 then  -- first frame
                    stream_info.frame_buffer = frame
                else
                    p = stream_info.frame_buffer
                    while p.next do
                        p = p.next
                    end
                    p.next = frame
                end
                stream_info.frame_buffer_size = stream_info.frame_buffer_size + 1
                
            else -- write data direct to file without sort or frame drop
                real_write_to_file(stream_info, str_bytes, begin_with_nalu_hdr)
            end
        end
        
        -- read RFC3984 about single nalu/stap-a/fu-a H264 payload format of rtp
        -- single NALU: one rtp payload contains only NALU
        local function process_single_nalu(stream_info, h264, timestamp, seq)
            write_to_file(stream_info, h264:tvb()():string(), true, timestamp, seq, true)
        end
        
        -- STAP-A: one rtp payload contains more than one NALUs
        local function process_stap_a(stream_info, h264, timestamp, seq)
            local h264tvb = h264:tvb()
            local offset = 1
            local i = 1
            repeat
                local size = h264tvb(offset,2):uint()
                write_to_file(stream_info, h264tvb(offset+2, size):string(), true, timestamp, i, true)
                offset = offset + 2 + size
                i = i + 1
            until offset >= h264tvb:len()
        end
        
        -- FU-A: one rtp payload contains only one part of a NALU (might be begin, middle and end part of a NALU)
        local function process_fu_a(stream_info, h264, timestamp, seq)
            local h264tvb = h264:tvb()
            local fu_idr = h264:get_index(0)
            local fu_hdr = h264:get_index(1)
            local end_of_nalu =  (bit.band(fu_hdr, 0x40) ~= 0)
            if bit.band(fu_hdr, 0x80) ~= 0 then
                -- start bit is set then save nalu header and body
                local nalu_hdr = bit.bor(bit.band(fu_idr, 0xE0), bit.band(fu_hdr, 0x1F))
                write_to_file(stream_info, string.char(nalu_hdr) .. h264tvb(2):string(), true, timestamp, seq, end_of_nalu)
            else
                -- start bit not set, just write part of nalu body
                write_to_file(stream_info, h264tvb(2):string(), false, timestamp, seq, end_of_nalu)
            end
        end
        
        -- call this function if a packet contains h264 payload
        function my_h264_tap.packet(pinfo,tvb)
            if stream_infos == nil then
                -- not triggered by button event, so do nothing.
                return
            end
            local h264s = { f_h264() } -- using table because one packet may contains more than one RTP
            local rtps = { f_rtp() }
            local rtp_seqs = { f_rtp_seq() }
            local rtp_timestamps = { f_rtp_timestamp() }
            
            for i,h264_f in ipairs(h264s) do
                if h264_f.len < 2 then
                    return
                end
                local h264 = h264_f.value   -- is ByteArray
                local hdr_type = bit.band(h264:get_index(0), 0x1F)
                local stream_info = get_stream_info(pinfo)
                
                -- search the RTP timestamp and sequence of this H264
                local timestamp = -1
                local seq = -1
                if drop_uncompleted_frame then
                    for j,rtp_f in ipairs(rtps) do
                        if h264_f.offset > rtp_f.offset and h264_f.offset - rtp_f.offset <= 16 and h264_f.offset+h264_f.len <= rtp_f.offset+rtp_f.len then
                            seq = rtp_seqs[j].value
                            timestamp = rtp_timestamps[j].value
			    break
                        end
                    end

                end
                
                if hdr_type > 0 and hdr_type < 24 then
                    -- Single NALU
                    process_single_nalu(stream_info, h264, timestamp, seq)
                elseif hdr_type == 24 then
                    -- STAP-A Single-time aggregation
                    process_stap_a(stream_info, h264, timestamp, seq)
                elseif hdr_type == 28 then
                    -- FU-A
                    process_fu_a(stream_info, h264, timestamp, seq)
                else
                    twappend("Error: unknown type=" .. hdr_type .. " ; we only know 1-23(Single NALU),24(STAP-A),28(FU-A)!")
                end
            end
        end
        
        -- close all open files
        local function close_all_files()
            if stream_infos then
                local no_streams = true
                for id,stream in pairs(stream_infos) do
                    if stream and stream.file then
                        if stream.frame_buffer then
                            local p = stream.frame_buffer
                            while p do
                                sort_and_write(stream, p)
                                p = p.next
                            end
                            stream.frame_buffer = nil
                            stream.frame_buffer_size = 0
                        end
                        stream.file:flush()
                        stream.file:close()
                        twappend("File [" .. stream.filename .. "] generated OK!\n")
                        stream.file = nil
                        no_streams = false
                    end
                end
                
                if no_streams then
                    twappend("Not found any H.264 over RTP streams!")
                end
            end
        end
        
        function my_h264_tap.reset()
            -- do nothing now
        end
        
        local function remove()
            my_h264_tap:remove()
        end
        
        tw:set_atclose(remove)
        
        local function export_h264(drop_frame)
            pgtw = ProgDlg.new("Export H264 to File Process", "Dumping H264 data to file...")
            first_run = true
            drop_uncompleted_frame = drop_frame
            stream_infos = {}
            -- first time it runs for counting h.264 packets and finding SPS and PPS
            retap_packets()
            first_run = false
            -- second time it runs for saving h264 data to target file.
            retap_packets()
            close_all_files()
            -- close progress window
            pgtw:close()
            stream_infos = nil
        end
        
        local function export_all()
            export_h264(false)
        end
        
        local function export_completed_frames()
            export_h264(true)
        end
        
        tw:add_button("Export All", export_all)
        tw:add_button("Export Completed Frames (Drop uncompleted frames)", export_completed_frames)
    end
    
    -- Find this feature in menu "Tools->"Export H264 to file [HQX's plugins]""
    register_menu("Export H264 to file [HQX's plugins]", export_h264_to_file, MENU_TOOLS_UNSORTED)
end

2015年升级版：

-- Dump RTP h.264 payload to raw h.264 file (*.264)
-- According to RFC3984 to dissector H264 payload of RTP to NALU, and write it
-- to from<sourceIp_sourcePort>to<dstIp_dstPort>.264 file. By now, we support single NALU,
-- STAP-A and FU-A format RTP payload for H.264.
-- You can access this feature by menu "Tools->Export H264 to file [HQX's plugins]"
-- Author: Huang Qiangxiong ([email protected])
-- change log:
--      2012-03-13
--          Just can play
--      2012-04-28
--          Add local to local function, and add [local bit = require("bit")] to prevent
--          bit recleared in previous file.
--      2013-07-11
--          Add sort RTP and drop uncompleted frame option.
--      2013-07-19
--          Do nothing when tap is triggered other than button event.
--          Add check for first or last packs lost of one frame.
--      2014-10-23
--          Fixed bug about print a frame.nalu_type error.
--      2014-11-07
--          Add support for Lua 5.2(>1.10.1) and 5.1(<=1.10.1). 
--          Change range:string() to range:raw().
--          Change h264_f.value to h264_f.range:bytes() because of wireshark lua bug.
--      2015-06-03
--          Fixed bug that if ipv6 address is using the file will not generated.(we replace ':' to '.')
------------------------------------------------------------------------------------------------
do
    --local bit = require("bit") -- only work before 1.10.1
    --local bit = require("bit32") -- only work after 1.10.1 (only support in Lua 5.2)
	local version_str = string.match(_VERSION, "%d+[.]%d*")
	local version_num = version_str and tonumber(version_str) or 5.1
	local bit = (version_num >= 5.2) and require("bit32") or require("bit")

    -- for geting h264 data (the field's value is type of ByteArray)
    local f_h264 = Field.new("h264") 
    local f_rtp = Field.new("rtp") 
    local f_rtp_seq = Field.new("rtp.seq")
    local f_rtp_timestamp = Field.new("rtp.timestamp")
    local nalu_type_list = {
        [0] = "Unspecified",
        [1] = "P/B_slice",
        [2] = "P/B_A",
        [3] = "P/B_B",
        [4] = "P/B_C",
        [5] = "I_slice",
        [6] = "SEI",
        [7] = "SPS",
        [8] = "PPS",
        [9] = "AUD",
    }
    
    local function get_enum_name(list, index)
        local value = list[index]
        return value and value or "Unknown"
    end

    -- menu action. When you click "Tools->Export H264 to file [HQX's plugins]" will run this function
    local function export_h264_to_file()
        -- window for showing information
        local tw = TextWindow.new("Export H264 to File Info Win")
        --local pgtw = ProgDlg.new("Export H264 to File Process", "Dumping H264 data to file...")
        local pgtw;
        
        -- add message to information window
        function twappend(str)
            tw:append(str)
            tw:append("\n")
        end
        
        -- running first time for counting and finding sps+pps, second time for real saving
        local first_run = true 
        -- variable for storing rtp stream and dumping parameters
        local stream_infos = nil
        -- drop_uncompleted_frame
        local drop_uncompleted_frame = false
        -- max frame buffer size
        local MAX_FRAME_NUM = 3

        -- trigered by all h264 packats
        local my_h264_tap = Listener.new(tap, "h264")
        
        -- get rtp stream info by src and dst address
        function get_stream_info(pinfo)
            local key = "from_" .. tostring(pinfo.src) .. "_" .. tostring(pinfo.src_port) .. "to" .. tostring(pinfo.dst) .. "_" .. tostring(pinfo.dst_port) .. (drop_uncompleted_frame and "_dropped" or "_all")
			key = key:gsub(":", ".")
            local stream_info = stream_infos[key]
            if not stream_info then -- if not exists, create one
                stream_info = { }
                stream_info.filename = key.. ".264"
                stream_info.file = io.open(stream_info.filename, "wb")
                stream_info.counter = 0 -- counting h264 total NALUs
                stream_info.counter2 = 0 -- for second time running
                stream_infos[key] = stream_info
                twappend("Ready to export H.264 data (RTP from " .. tostring(pinfo.src) .. ":" .. tostring(pinfo.src_port) 
                         .. " to " .. tostring(pinfo.dst) .. ":" .. tostring(pinfo.dst_port) .. " to file:\n         [" .. stream_info.filename .. "] ...\n")
            end
            return stream_info
        end
        
        -- write a NALU or part of NALU to file.
        local function real_write_to_file(stream_info, str_bytes, begin_with_nalu_hdr)
            if first_run then
                stream_info.counter = stream_info.counter + 1
                
                if begin_with_nalu_hdr then
                    -- save SPS or PPS
                    local nalu_type = bit.band(str_bytes:byte(0,1), 0x1F)
                    if not stream_info.sps and nalu_type == 7 then
                        stream_info.sps = str_bytes
                    elseif not stream_info.pps and nalu_type == 8 then
                        stream_info.pps = str_bytes
                    end
                end
                
            else -- second time running
                --[[
                if begin_with_nalu_hdr then
                    -- drop AUD
                    local nalu_type = bit.band(str_bytes:byte(0,1), 0x1F)
                    if nalu_type == 9 then
                        return;
                    end
                end
                ]]
                
                if stream_info.counter2 == 0 then
                    -- write SPS and PPS to file header first
                    if stream_info.sps then
                        stream_info.file:write("\00\00\00\01")
                        stream_info.file:write(stream_info.sps)
                    else
                        twappend("Not found SPS for [" .. stream_info.filename .. "], it might not be played!\n")
                    end
                    if stream_info.pps then
                        stream_info.file:write("\00\00\00\01")
                        stream_info.file:write(stream_info.pps)
                    else
                        twappend("Not found PPS for [" .. stream_info.filename .. "], it might not be played!\n")
                    end
                end
            
                if begin_with_nalu_hdr then
                    -- *.264 raw file format seams that every nalu start with 0x00000001
                    stream_info.file:write("\00\00\00\01")
                end
                stream_info.file:write(str_bytes)
                stream_info.counter2 = stream_info.counter2 + 1

                -- update progress window's progress bar
                if stream_info.counter > 0 and stream_info.counter2 < stream_info.counter then pgtw:update(stream_info.counter2 / stream_info.counter) end
            end
        end
        
        local function comp_pack(p1, p2)
            if math.abs(p2.seq - p1.seq) < 1000 then
                return p1.seq < p2.seq
            else -- seqeunce is over 2^16, so the small one is much big
                return p1.seq > p2.seq
            end
        end
        
        local function print_seq_error(stream_info, str)
            if stream_info.seq_error_counter == nil then
                stream_info.seq_error_counter = 0
            end
            stream_info.seq_error_counter = stream_info.seq_error_counter + 1
            twappend(str .. " SeqErrCounts=" .. stream_info.seq_error_counter)
        end
        
        local function sort_and_write(stream_info, frame)
            table.sort(frame.packs, comp_pack)
            
            -- check if it is uncompleted frame
            local completed = true
            for i = 1, #frame.packs - 1, 1 do
                local seq1 = frame.packs[i].seq
                local seq2 = frame.packs[i+1].seq
                if bit.band(seq1+1, 0xFFFF) ~= seq2 then
                    print_seq_error(stream_info, " RTP pack Lost: timestamp=" .. frame.timestamp .. " seq between " .. seq1 .. " and " .. seq2)
                    completed = false
                end
            end
            
            if not frame.packs[1].nalu_begin then
                print_seq_error(stream_info, " RTP pack Lost: timestamp=" .. frame.timestamp .. " seq before " .. frame.packs[1].seq)
                completed = false
            end
            
            if not frame.packs[#frame.packs].nalu_end then
                print_seq_error(stream_info, " RTP pack Lost: timestamp=" .. frame.timestamp .. " seq after " .. frame.packs[#frame.packs].seq)
                completed = false
            end
            
            if completed then
                for i = 1, #frame.packs, 1 do
                    real_write_to_file(stream_info, frame.packs[i].data, frame.packs[i].nalu_begin)
                end
            else
                twappend("   We drop one uncompleted frame: rtp.timestamp=" .. frame.timestamp 
                         .. " nalu_type=" .. (frame.nalu_type and frame.nalu_type .."(" .. get_enum_name(nalu_type_list, frame.nalu_type) .. ")" or "unknown") )
            end
        end
        
        local function write_to_file(stream_info, str_bytes, begin_with_nalu_hdr, timestamp, seq, end_of_nalu)
            if drop_uncompleted_frame and not first_run then -- sort and drop uncompleted frame
                if stream_info.frame_buffer_size == nil then
                    stream_info.frame_buffer_size = 0
                end
                
                if timestamp < 0 or seq < 0 then
                    twappend(" Invalid rtp timestamp (".. timestamp .. ") or seq (".. seq .. ")! We have to write it to file directly!")
                    real_write_to_file(stream_info, str_bytes, begin_with_nalu_hdr)
                    return;
                end
                
                -- check if this frame has existed
                local p = stream_info.frame_buffer
                while p do
                    if p.timestamp == timestamp then
                        break;
                    else
                        p = p.next
                    end
                end
                
                if p then  -- add this pack to frame
                    if begin_with_nalu_hdr then
                        p.nalu_type = bit.band(str_bytes:byte(1), 0x1F)
                    end
                    table.insert(p.packs, { ["seq"] = seq, ["data"] = str_bytes , ["nalu_begin"] = begin_with_nalu_hdr, ["nalu_end"] = end_of_nalu })
                    return
                end
                
                if stream_info.frame_buffer_size >= MAX_FRAME_NUM then
                    -- write the most early frame to file
                    sort_and_write(stream_info, stream_info.frame_buffer)
                    stream_info.frame_buffer = stream_info.frame_buffer.next
                    stream_info.frame_buffer_size = stream_info.frame_buffer_size - 1
                end
                
                -- create a new frame buffer for new frame (timestamp)
                local frame = {}
                frame.timestamp = timestamp
                if begin_with_nalu_hdr then
                    frame.nalu_type = bit.band(str_bytes:byte(1), 0x1F)
                end
                frame.packs = {{ ["seq"] = seq, ["data"] = str_bytes, ["nalu_begin"] = begin_with_nalu_hdr, ["nalu_end"] = end_of_nalu}}  -- put pack to index 1 pos
                frame.next = nil
                
                if stream_info.frame_buffer_size == 0 then  -- first frame
                    stream_info.frame_buffer = frame
                else
                    p = stream_info.frame_buffer
                    while p.next do
                        p = p.next
                    end
                    p.next = frame
                end
                stream_info.frame_buffer_size = stream_info.frame_buffer_size + 1
                
            else -- write data direct to file without sort or frame drop
                real_write_to_file(stream_info, str_bytes, begin_with_nalu_hdr)
            end
        end
        
        -- read RFC3984 about single nalu/stap-a/fu-a H264 payload format of rtp
        -- single NALU: one rtp payload contains only NALU
        local function process_single_nalu(stream_info, h264, timestamp, seq)
            --write_to_file(stream_info, h264:tvb()():string(), true, timestamp, seq, true)
			write_to_file(stream_info, ((version_num >= 5.2) and h264:tvb():raw() or h264:tvb()():string()), true, timestamp, seq, true)
        end
        
        -- STAP-A: one rtp payload contains more than one NALUs
        local function process_stap_a(stream_info, h264, timestamp, seq)
            local h264tvb = h264:tvb()
            local offset = 1
            local i = 1
            repeat
                local size = h264tvb(offset,2):uint()
                --write_to_file(stream_info, h264tvb(offset+2, size):string(), true, timestamp, i, true)
				write_to_file(stream_info, ((version_num >= 5.2) and h264tvb:raw(offset+2, size) or h264tvb(offset+2, size):string()), true, timestamp, i, true)
                offset = offset + 2 + size
                i = i + 1
            until offset >= h264tvb:len()
        end
        
        -- FU-A: one rtp payload contains only one part of a NALU (might be begin, middle and end part of a NALU)
        local function process_fu_a(stream_info, h264, timestamp, seq)
            local h264tvb = h264:tvb()
            local fu_idr = h264:get_index(0)
            local fu_hdr = h264:get_index(1)
            local end_of_nalu =  (bit.band(fu_hdr, 0x40) ~= 0)
            if bit.band(fu_hdr, 0x80) ~= 0 then
                -- start bit is set then save nalu header and body
                local nalu_hdr = bit.bor(bit.band(fu_idr, 0xE0), bit.band(fu_hdr, 0x1F))
                --write_to_file(stream_info, string.char(nalu_hdr) .. h264tvb(2):string(), true, timestamp, seq, end_of_nalu)
				write_to_file(stream_info, string.char(nalu_hdr) .. ((version_num >= 5.2) and h264tvb:raw(2) or h264tvb(2):string()), true, timestamp, seq, end_of_nalu)
            else
                -- start bit not set, just write part of nalu body
                --write_to_file(stream_info, h264tvb(2):string(), false, timestamp, seq, end_of_nalu)
				write_to_file(stream_info, ((version_num >= 5.2) and h264tvb:raw(2) or h264tvb(2):string()), false, timestamp, seq, end_of_nalu)
            end
        end
        
        -- call this function if a packet contains h264 payload
        function my_h264_tap.packet(pinfo,tvb)
            if stream_infos == nil then
                -- not triggered by button event, so do nothing.
                return
            end
            local h264s = { f_h264() } -- using table because one packet may contains more than one RTP
            local rtps = { f_rtp() }
            local rtp_seqs = { f_rtp_seq() }
            local rtp_timestamps = { f_rtp_timestamp() }
            
            for i,h264_f in ipairs(h264s) do
                if h264_f.len < 2 then
                    return
                end
                --local h264 = h264_f.value   -- is ByteArray, it only works for 1.10.1 or early version
				--local h264 = h264_f.range:bytes()   -- according to user-guide.chm, there is a bug of fieldInfo.value, so we have to convert it to TVB range first
				local h264 = (version_num >= 5.2) and h264_f.range:bytes() or h264_f.value 
                local hdr_type = bit.band(h264:get_index(0), 0x1F)
                local stream_info = get_stream_info(pinfo)
--twappend(string.format("hdr_type=%X %d", hdr_type, hdr_type)) 
--twappend("bytearray=" .. tostring(h264))
--twappend("byterange=" .. tostring(h264_f.range):upper())
                -- search the RTP timestamp and sequence of this H264
                local timestamp = -1
                local seq = -1
				-- debug begin
				local rtplen = -1
				local preh264_foffset = -1
				local prertp_foffset = -1
				local preh264len = -1
				-- debug end
                if drop_uncompleted_frame then
					local matchx = 0;
                    for j,rtp_f in ipairs(rtps) do
                        if h264_f.offset > rtp_f.offset and h264_f.offset - rtp_f.offset <= 16 and h264_f.offset+h264_f.len <= rtp_f.offset+rtp_f.len then
						-- debug begin
						--if h264_f.offset > rtp_f.offset and h264_f.offset < rtp_f.offset+rtp_f.len then
					matchx = matchx + 1
					if matchx > 1 then
						print_seq_error(stream_info, "ASS seq=" .. seq .. " timestamp=" .. timestamp .. " rtplen=" .. rtplen .. " rtpoff=" .. prertp_foffset .. " h264off=" .. preh264_foffset .. " h264len=" .. preh264len .. "  |matched=" .. matchx .. "  New seq=" .. rtp_seqs[j].value .. " timestamp=" .. rtp_timestamps[j].value .. " rtplen=" .. rtp_f.len .." rtpoff=" .. rtp_f.offset .. " h264off=" .. h264_f.offset .. " h264.len=" .. h264_f.len)
					end		 
					-- debug end
                            seq = rtp_seqs[j].value
                            timestamp = rtp_timestamps[j].value
							-- debug begin
							rtplen = rtp_f.len
							preh264_foffset = h264_f.offset
							prertp_foffset = rtp_f.offset
							preh264len = h264_f.len
							-- debug end
							break
                        end
                    end

                end
                
                if hdr_type > 0 and hdr_type < 24 then
                    -- Single NALU
                    process_single_nalu(stream_info, h264, timestamp, seq)
                elseif hdr_type == 24 then
                    -- STAP-A Single-time aggregation
                    process_stap_a(stream_info, h264, timestamp, seq)
                elseif hdr_type == 28 then
                    -- FU-A
                    process_fu_a(stream_info, h264, timestamp, seq)
                else
                    twappend("Error: unknown type=" .. hdr_type .. " ; we only know 1-23(Single NALU),24(STAP-A),28(FU-A)!")
                end
            end
        end
        
        -- close all open files
        local function close_all_files()
            if stream_infos then
                local no_streams = true
                for id,stream in pairs(stream_infos) do
                    if stream and stream.file then
                        if stream.frame_buffer then
                            local p = stream.frame_buffer
                            while p do
                                sort_and_write(stream, p)
                                p = p.next
                            end
                            stream.frame_buffer = nil
                            stream.frame_buffer_size = 0
                        end
                        stream.file:flush()
                        stream.file:close()
                        twappend("File [" .. stream.filename .. "] generated OK!\n")
                        stream.file = nil
                        no_streams = false
                    end
                end
                
                if no_streams then
                    twappend("Not found any H.264 over RTP streams!")
                end
            end
        end
        
        function my_h264_tap.reset()
            -- do nothing now
        end
        
        local function remove()
            my_h264_tap:remove()
        end
        
        tw:set_atclose(remove)
        
        local function export_h264(drop_frame)
            pgtw = ProgDlg.new("Export H264 to File Process", "Dumping H264 data to file...")
            first_run = true
            drop_uncompleted_frame = drop_frame
            stream_infos = {}
            -- first time it runs for counting h.264 packets and finding SPS and PPS
            retap_packets()
            first_run = false
            -- second time it runs for saving h264 data to target file.
            retap_packets()
            close_all_files()
            -- close progress window
            pgtw:close()
            stream_infos = nil
        end
        
        local function export_all()
            export_h264(false)
        end
        
        local function export_completed_frames()
            export_h264(true)
        end
        
        tw:add_button("Export All", export_all)
        tw:add_button("Export Completed Frames (Drop uncompleted frames)", export_completed_frames)
    end
    
    -- Find this feature in menu "Tools->"Export H264 to file [HQX's plugins]""
    register_menu("Export H264 to file [HQX's plugins]", export_h264_to_file, MENU_TOOLS_UNSORTED)
end