c++视频编辑代码小结
》视频编辑实现有以下几个方案：
ffmpeg+android/ios， 参考代码很多，跨平台。
openmax （AL编程） + android： openmx参考例子比较少，
gpuImage 开源ios框架，支持视频剪辑滤镜等功能；
参考：开源alure-1.2.tar http://kcat.strangesoft.net/index.html
demo: http://kcat.strangesoft.net/alffmpeg.c/*
有一些demo参考，未测试，慎用
http://kcat.strangesoft.net/alffmpeg.c
* This program is free software. It comes without any warranty, to
* the extent permitted by applicable law. You can redistribute it
* and/or modify it under the terms of the Do What The Fuck You Want
* To Public License, Version 2, as published by Sam Hocevar. See
* http://sam.zoy.org/wtfpl/COPYING for more details.
*/
/* ChangeLog:
* 1 - Initial program
* 2 - Changed getAVAudioData to not always grab another packet before decoding
* to prevent buffering more compressed data than needed
* 3 - Update to use avcodec_decode_audio3 and fix for decoders that need
* aligned output pointers
* 4 - Fixed bits/channels format assumption
* 5 - Improve time handling
* 6 - Remove use of ALUT
*/
#include
#include
#include
#include
#include
#include
#include
#include
#ifndef _WIN32
#include
#define Sleep(x) usleep((x)*1000)
#else
#define WIN32_LEAN_AND_MEAN
#include
#endif
/* Opaque handles to files and streams. The main app doesn't need to concern
* itself with the internals */
typedef struct MyFile *FilePtr;
typedef struct MyStream *StreamPtr;
#ifndef AL_SOFT_buffer_samples
/* Sample types */
#define AL_BYTE 0x1400
#define AL_UNSIGNED_BYTE 0x1401
#define AL_SHORT 0x1402
#define AL_UNSIGNED_SHORT 0x1403
#define AL_INT 0x1404
#define AL_UNSIGNED_INT 0x1405
#define AL_FLOAT 0x1406
#define AL_DOUBLE 0x1407
/* Channel configurations */
#define AL_MONO 0x1500
#define AL_STEREO 0x1501
#define AL_REAR 0x1502
#define AL_QUAD 0x1503
#define AL_5POINT1 0x1504 /* (WFX order) */
#define AL_6POINT1 0x1505 /* (WFX order) */
#define AL_7POINT1 0x1506 /* (WFX order) */
#endif
/**** Helper functions ****/
#include
#include
typedef struct PacketList {
AVPacket pkt;
struct PacketList *next;
} PacketList;
struct MyStream {
AVCodecContext *CodecCtx;
int StreamIdx;
PacketList *Packets;
char *DecodedData;
size_t DecodedDataSize;
FilePtr parent;
};
struct MyFile {
AVFormatContext *FmtCtx;
StreamPtr *Streams;
size_t StreamsSize;
};
/* This opens a file with ffmpeg and sets up the streams' information */
FilePtr openAVFile(const char *fname)
{
static int done = 0;
FilePtr file;
/* We need to make sure ffmpeg is initialized. Optionally silence warning
* output from the lib */
if(!done) {av_register_all();
av_log_set_level(AV_LOG_ERROR);
done = 1;}
file = (FilePtr)calloc(1, sizeof(*file));
if(file && avformat_open_input(&file->FmtCtx, fname, NULL, NULL) == 0)
{
/* After opening, we must search for the stream information because not
* all formats will have it in stream headers */
if(av_find_stream_info(file->FmtCtx) >= 0)
return file;
av_close_input_file(file->FmtCtx);
}
free(file);
return NULL;
}
/* This closes/frees an opened file and any of its streams. Pretty self-
* explanitory... */
void closeAVFile(FilePtr file)
{
size_t i;
if(!file) return;
for(i = 0;i < file->StreamsSize;i++)
{
StreamPtr stream = file->Streams[i];
while(stream->Packets)
{
PacketList *self = stream->Packets;
stream->Packets = self->next;
av_free_packet(&self->pkt);
av_free(self);
}
avcodec_close(stream->CodecCtx);
av_free(stream->DecodedData);
free(stream);
}
free(file->Streams);
av_close_input_file(file->FmtCtx);
free(file);
}
/* This reports certain information from the file, eg, the number of audio
* streams */
int getAVFileInfo(FilePtr file, int *numaudiostreams)
{
unsigned int i;
int audiocount = 0;
if(!file) return 1;
for(i = 0;i < file->FmtCtx->nb_streams;i++)
{
if(file->FmtCtx->streams[i]->codec->codec_type == CODEC_TYPE_AUDIO)
audiocount++;
}
*numaudiostreams = audiocount;
return 0;
}
/* This retrieves a handle for the given audio stream number (generally 0, but
* some files can have multiple audio streams in one file) */
StreamPtr getAVAudioStream(FilePtr file, int streamnum)
{
unsigned int i;
if(!file) return NULL;
for(i = 0;i < file->FmtCtx->nb_streams;i++)
{
if(file->FmtCtx->streams[i]->codec->codec_type != CODEC_TYPE_AUDIO)
continue;
if(streamnum == 0)
{
StreamPtr stream;
AVCodec *codec;
void *temp;
size_t j;
/* Found the requested stream. Check if a handle to this stream
* already exists and return it if it does */
for(j = 0;j < file->StreamsSize;j++)
{
if(file->Streams[j]->StreamIdx == (int)i)
return file->Streams[j];
}
/* Doesn't yet exist. Now allocate a new stream object and fill in
* its info */
stream = (StreamPtr)calloc(1, sizeof(*stream));
if(!stream) return NULL;
stream->parent = file;
stream->CodecCtx = file->FmtCtx->streams[i]->codec;
stream->StreamIdx = i;
/* Try to find the codec for the given codec ID, and open it */
codec = avcodec_find_decoder(stream->CodecCtx->codec_id);
if(!codec || avcodec_open(stream->CodecCtx, codec) < 0)
{
free(stream);
return NULL;
}
/* Allocate space for the decoded data to be stored in before it
* gets passed to the app */
stream->DecodedData = av_malloc(AVCODEC_MAX_AUDIO_FRAME_SIZE);
if(!stream->DecodedData)
{
avcodec_close(stream->CodecCtx);
free(stream);
return NULL;
}
/* Append the new stream object to the stream list. The original
* pointer will remain valid if realloc fails, so we need to use
* another pointer to watch for errors and not leak memory */
temp = realloc(file->Streams, (file->StreamsSize+1) *
sizeof(*file->Streams));
if(!temp)
{
avcodec_close(stream->CodecCtx);
av_free(stream->DecodedData);
free(stream);
return NULL;
}
file->Streams = (StreamPtr*)temp;
file->Streams[file->StreamsSize++] = stream;
return stream;
}
streamnum--;
}
return NULL;
}
/* Returns information about the given audio stream. Returns 0 on success. */
int getAVAudioInfo(StreamPtr stream, ALuint *rate, ALenum *channels, ALenum *type)
{
if(!stream || stream->CodecCtx->codec_type != CODEC_TYPE_AUDIO)
return 1;
if(type)
{
if(stream->CodecCtx->sample_fmt == AV_SAMPLE_FMT_U8)
*type = AL_UNSIGNED_BYTE;
else if(stream->CodecCtx->sample_fmt == AV_SAMPLE_FMT_S16)
*type = AL_SHORT;
else if(stream->CodecCtx->sample_fmt == AV_SAMPLE_FMT_S32)
*type = AL_INT;
else if(stream->CodecCtx->sample_fmt == AV_SAMPLE_FMT_FLT)
*type = AL_FLOAT;
else if(stream->CodecCtx->sample_fmt == AV_SAMPLE_FMT_DBL)
*type = AL_DOUBLE;
else
return 1;
}
if(channels)
{
if(stream->CodecCtx->channel_layout == AV_CH_LAYOUT_MONO)
*channels = AL_MONO;
else if(stream->CodecCtx->channel_layout == AV_CH_LAYOUT_STEREO)
*channels = AL_STEREO;
else if(stream->CodecCtx->channel_layout == AV_CH_LAYOUT_QUAD)
*channels = AL_QUAD;
else if(stream->CodecCtx->channel_layout == AV_CH_LAYOUT_5POINT1)
*channels = AL_5POINT1;
else if(stream->CodecCtx->channel_layout == AV_CH_LAYOUT_7POINT1)
*channels = AL_7POINT1;
else
return 1;
}
if(rate) *rate = stream->CodecCtx->sample_rate;
return 0;
}
/* Used by getAV*Data to search for more compressed data, and buffer it in the
* correct stream. It won't buffer data for streams that the app doesn't have a
* handle for. */
static int getNextPacket(FilePtr file, int streamidx)
{
PacketList *packet = (PacketList*)av_malloc(sizeof(PacketList));
packet->next = NULL;
next_pkt:
while(av_read_frame(file->FmtCtx, &packet->pkt) >= 0)
{
StreamPtr *iter = file->Streams;
StreamPtr *iter_end = iter + file->StreamsSize;
/* Check each stream the user has a handle for, looking for the one
* this packet belongs to */
while(iter != iter_end)
{
if((*iter)->StreamIdx == packet->pkt.stream_index)
{
PacketList **last = &(*iter)->Packets;
while(*last != NULL)
last = &(*last)->next;
*last = packet;
if((*iter)->StreamIdx == streamidx)
return 1;
packet = (PacketList*)av_malloc(sizeof(PacketList));
packet->next = NULL;
goto next_pkt;
}
iter++;
}
/* Free the packet and look for another */
av_free_packet(&packet->pkt);
}
av_free(packet);
return 0;
}
/* The "meat" function. Decodes audio and writes, at most, length bytes into
* the provided data buffer. Will only return less for end-of-stream or error
* conditions. Returns the number of bytes written. */
int getAVAudioData(StreamPtr stream, void *data, int length)
{
int dec = 0;
if(!stream || stream->CodecCtx->codec_type != CODEC_TYPE_AUDIO)
return 0;
while(dec < length)
{
/* If there's no decoded data, find some */
if(stream->DecodedDataSize == 0)
{
int size;
int len;
/* If there's no more input data, break and return what we have */
if(!stream->Packets &&
!getNextPacket(stream->parent, stream->StreamIdx))
break;
/* Decode some data, and check for errors */
size = AVCODEC_MAX_AUDIO_FRAME_SIZE;
while((len=avcodec_decode_audio3(stream->CodecCtx,
(int16_t*)stream->DecodedData, &size,
&stream->Packets->pkt)) == 0)
{
PacketList *self;
if(size > 0)
break;
self = stream->Packets;
stream->Packets = self->next;
av_free_packet(&self->pkt);
av_free(self);
if(!stream->Packets)
break;
}
if(!stream->Packets)
continue;
if(len < 0)
break;
if(len > 0)
{
if(len < stream->Packets->pkt.size)
{
/* Move the remaining data to the front and clear the end
* bits */
int remaining = stream->Packets->pkt.size - len;
memmove(stream->Packets->pkt.data,
&stream->Packets->pkt.data[len],
remaining);
memset(&stream->Packets->pkt.data[remaining], 0,
stream->Packets->pkt.size - remaining);
stream->Packets->pkt.size -= len;
}
else
{
PacketList *self = stream->Packets;
stream->Packets = self->next;
av_free_packet(&self->pkt);
av_free(self);
}
}
/* Set the output buffer size */
stream->DecodedDataSize = size;
}
if(stream->DecodedDataSize > 0)
{
/* Get the amount of bytes remaining to be written, and clamp to
* the amount of decoded data we have */
size_t rem = length-dec;
if(rem > stream->DecodedDataSize)
rem = stream->DecodedDataSize;
/* Copy the data to the app's buffer and increment */
memcpy(data, stream->DecodedData, rem);
data = (char*)data + rem;
dec += rem;
/* If there's any decoded data left, move it to the front of the
* buffer for next time */
if(rem < stream->DecodedDataSize)
memmove(stream->DecodedData, &stream->DecodedData[rem],
stream->DecodedDataSize - rem);
stream->DecodedDataSize -= rem;
}
}
/* Return the number of bytes we were able to get */
return dec;
}
/**** The main app ****/
/* Create a simple signal handler for SIGINT so ctrl-c cleanly exits. */
static volatile int quitnow = 0;
static void handle_sigint(int signum)
{
quitnow = 1;
signal(signum, SIG_DFL);
}
/* Some helper functions to get the name from the channel and type enums. */
static const char *ChannelsName(ALenum chans)
{
switch(chans)
{
case AL_MONO: return "Mono";
case AL_STEREO: return "Stereo";
case AL_REAR: return "Rear";
case AL_QUAD: return "Quadraphonic";
case AL_5POINT1: return "5.1 Surround";
case AL_6POINT1: return "6.1 Surround";
case AL_7POINT1: return "7.1 Surround";
}
return "Unknown";
}
static const char *TypeName(ALenum type)
{
switch(type)
{
case AL_BYTE: return "S8";
case AL_UNSIGNED_BYTE: return "U8";
case AL_SHORT: return "S16";
case AL_UNSIGNED_SHORT: return "U16";
case AL_INT: return "S32";
case AL_UNSIGNED_INT: return "U32";
case AL_FLOAT: return "Float32";
case AL_DOUBLE: return "Float64";
}
return "Unknown";
}
/* Define the number of buffers and buffer size (in bytes) to use. 3 buffers is
* a good amount (one playing, one ready to play, another being filled). 32256
* is a good length per buffer, as it fits 1, 2, 4, 6, 7, 8, 12, 14, 16, 24,
* 28, and 32 bytes-per-frame sizes. */
#define NUM_BUFFERS 3
#define BUFFER_SIZE 32256
int main(int argc, char **argv)
{
/* The device and context handles to play with */
ALCdevice *device;
ALCcontext *ctx;
/* Here are the buffers and source to play out through OpenAL with */
ALuint buffers[NUM_BUFFERS];
ALuint source;
ALint state; /* This will hold the state of the source */
ALbyte *data; /* A temp data buffer for getAVAudioData to write to and pass
* to OpenAL with */
int count; /* The number of bytes read from getAVAudioData */
int i; /* An iterator for looping over the filenames */
/* Print out usage if no file was specified */
if(argc < 2)
{
fprintf(stderr, "Usage: %s \n", argv[0]);
return 1;
}
/* Set up our signal handler to run on SIGINT (ctrl-c) */
if(signal(SIGINT, handle_sigint) == SIG_ERR)
{
fprintf(stderr, "Unable to set handler for SIGINT!\n");
return 1;
}
/* Open and initialize a device with default settings */
device = alcOpenDevice(NULL);
if(!device)
{
fprintf(stderr, "Could not open a device!\n");
return 1;
}
ctx = alcCreateContext(device, NULL);
if(ctx == NULL || alcMakeContextCurrent(ctx) == ALC_FALSE)
{
if(ctx != NULL)
alcDestroyContext(ctx);
alcCloseDevice(device);
fprintf(stderr, "Could not set a context!\n");
return 1;
}
/* Generate the buffers and source */
alGenBuffers(NUM_BUFFERS, buffers);
if(alGetError() != AL_NO_ERROR)
{
alcMakeContextCurrent(NULL);
alcDestroyContext(ctx);
alcCloseDevice(device);
fprintf(stderr, "Could not create buffers...\n");
return 1;
}
alGenSources(1, &source);
if(alGetError() != AL_NO_ERROR)
{
alDeleteBuffers(NUM_BUFFERS, buffers);
alcMakeContextCurrent(NULL);
alcDestroyContext(ctx);
alcCloseDevice(device);
fprintf(stderr, "Could not create source...\n");
return 1;
}
/* Set parameters so mono sources won't distance attenuate */
alSourcei(source, AL_SOURCE_RELATIVE, AL_TRUE);
alSourcei(source, AL_ROLLOFF_FACTOR, 0);
if(alGetError() != AL_NO_ERROR)
{
alDeleteSources(1, &source);
alDeleteBuffers(NUM_BUFFERS, buffers);
alcMakeContextCurrent(NULL);
alcDestroyContext(ctx);
alcCloseDevice(device);
fprintf(stderr, "Could not set source parameters...\n");
return 1;
}
data = malloc(BUFFER_SIZE);
if(data == NULL)
{
alDeleteSources(1, &source);
alDeleteBuffers(NUM_BUFFERS, buffers);
alcMakeContextCurrent(NULL);
alcDestroyContext(ctx);
alcCloseDevice(device);
fprintf(stderr, "Could not create temp buffer...\n");
return 1;
}
/* Play each file listed on the command line */
for(i = 1;i < argc && !quitnow;i++)
{
static ALenum old_format;
static ALuint old_rate;
/* The base time to use when determining the playback time from the
* source. */
static int64_t basetime;
static int64_t filetime;
/* Handles for the audio stream */
FilePtr file;
StreamPtr stream;
/* The format of the output stream */
ALenum format = 0;
ALenum channels;
ALenum type;
ALuint rate;
/* Open the file and get the first stream from it */
file = openAVFile(argv[i]);
stream = getAVAudioStream(file, 0);
if(!stream)
{
closeAVFile(file);
fprintf(stderr, "Could not open audio in %s\n", argv[i]);
continue;
}
/* Get the stream format, and figure out the OpenAL format. We use the
* AL_EXT_MCFORMATS extension to provide output of Quad, 5.1, and 7.1
* audio streams */
if(getAVAudioInfo(stream, &rate, &channels, &type) != 0)
{
closeAVFile(file);
fprintf(stderr, "Error getting audio info for %s\n", argv[i]);
continue;
}
if(type == AL_UNSIGNED_BYTE)
{
if(channels == AL_MONO) format = AL_FORMAT_MONO8;
else if(channels == AL_STEREO) format = AL_FORMAT_STEREO8;
else if(alIsExtensionPresent("AL_EXT_MCFORMATS"))
{
if(channels == AL_QUAD) format = alGetEnumValue("AL_FORMAT_QUAD8");
else if(channels == AL_5POINT1) format = alGetEnumValue("AL_FORMAT_51CHN8");
else if(channels == AL_7POINT1) format = alGetEnumValue("AL_FORMAT_71CHN8");
}
}
else if(type == AL_SHORT)
{
if(channels == AL_MONO) format = AL_FORMAT_MONO16;
else if(channels == AL_STEREO) format = AL_FORMAT_STEREO16;
else if(alIsExtensionPresent("AL_EXT_MCFORMATS"))
{
if(channels == AL_QUAD) format = alGetEnumValue("AL_FORMAT_QUAD16");
else if(channels == AL_5POINT1) format = alGetEnumValue("AL_FORMAT_51CHN16");
else if(channels == AL_7POINT1) format = alGetEnumValue("AL_FORMAT_71CHN16");
}
}
else if(type == AL_FLOAT && alIsExtensionPresent("AL_EXT_FLOAT32"))
{
if(channels == AL_MONO) format = alGetEnumValue("AL_FORMAT_MONO_FLOAT32");
else if(channels == AL_STEREO) format = alGetEnumValue("AL_FORMAT_STEREO_FLOAT32");
else if(alIsExtensionPresent("AL_EXT_MCFORMATS"))
{
if(channels == AL_QUAD) format = alGetEnumValue("AL_FORMAT_QUAD32");
else if(channels == AL_5POINT1) format = alGetEnumValue("AL_FORMAT_51CHN32");
else if(channels == AL_7POINT1) format = alGetEnumValue("AL_FORMAT_71CHN32");
}
}
else if(type == AL_DOUBLE && alIsExtensionPresent("AL_EXT_DOUBLE"))
{
if(channels == AL_MONO) format = alGetEnumValue("AL_FORMAT_MONO_DOUBLE");
else if(channels == AL_STEREO) format = alGetEnumValue("AL_FORMAT_STEREO_DOUBLE");
}
if(format == 0 || format == -1)
{
closeAVFile(file);
fprintf(stderr, "Unhandled format (%s, %s) for %s",
ChannelsName(channels), TypeName(type), argv[i]);
continue;
}
/* If the format of the last file matches the current one, we can skip
* the initial load and let the processing loop take over (gap-less
* playback!) */
count = 1;
if(format == old_format && rate == old_rate)
{
/* When skipping the initial load of a file (because the previous
* one is using the same exact format), just remove the length of
* the previous file from the base. This is so the timing will be
* from the beginning of this file, which won't start playing until
* the next buffer to get queued does */
basetime -= filetime;
filetime = 0;
}
else
{
int j;
/* Wait for the last song to finish playing */
do {
Sleep(10);
alGetSourcei(source, AL_SOURCE_STATE, &state);
} while(alGetError() == AL_NO_ERROR && state == AL_PLAYING);
/* Rewind the source position and clear the buffer queue */
alSourceRewind(source);
alSourcei(source, AL_BUFFER, 0);
/* Reset old variables */
basetime = 0;
filetime = 0;
old_format = format;
old_rate = rate;
/* Fill and queue the buffers */
for(j = 0;j < NUM_BUFFERS;j++)
{
ALint size, numchans, numbits;
/* Make sure we get some data to give to the buffer */
count = getAVAudioData(stream, data, BUFFER_SIZE);
if(count <= 0) break;
/* Buffer the data with OpenAL and queue the buffer onto the
* source */
alBufferData(buffers[j], format, data, count, rate);
alSourceQueueBuffers(source, 1, &buffers[j]);
/* For each successful buffer queued, increment the filetime */
alGetBufferi(buffers[j], AL_SIZE, &size);
alGetBufferi(buffers[j], AL_CHANNELS, &numchans);
alGetBufferi(buffers[j], AL_BITS, &numbits);
filetime += size / numchans * 8 / numbits;
}
/* Now start playback! */
alSourcePlay(source);
if(alGetError() != AL_NO_ERROR)
{
closeAVFile(file);
fprintf(stderr, "Error starting playback...\n");
continue;
}
}
fprintf(stderr, "Playing %s (%s, %s, %dhz)\n", argv[i],
TypeName(type), ChannelsName(channels), rate);
while(count > 0 && !quitnow)
{
/* Check if any buffers on the source are finished playing */
ALint processed = 0;
alGetSourcei(source, AL_BUFFERS_PROCESSED, &processed);
if(processed == 0)
{
/* All buffers are full. Check if the source is still playing.
* If not, restart it, otherwise, print the time and rest */
alGetSourcei(source, AL_SOURCE_STATE, &state);
if(alGetError() != AL_NO_ERROR)
{
fprintf(stderr, "\nError checking source state...\n");
break;
}
if(state != AL_PLAYING)
{
alSourcePlay(source);
if(alGetError() != AL_NO_ERROR)
{
closeAVFile(file);
fprintf(stderr, "\nError restarting playback...\n");
break;
}
}
else
{
int64_t curtime = 0;
if(basetime >= 0)
{
ALint offset = 0;
alGetSourcei(source, AL_SAMPLE_OFFSET, &offset);
curtime = basetime + offset;
}
fprintf(stderr, "\rTime: %ld:%05.02f", (long)(curtime/rate/60),
(float)(curtime%(rate*60))/(float)rate);
Sleep(10);
}
continue;
}
/* Read the next chunk of data and refill the oldest buffer */
count = getAVAudioData(stream, data, BUFFER_SIZE);
if(count > 0)
{
ALuint buf = 0;
alSourceUnqueueBuffers(source, 1, &buf);
if(buf != 0)
{
ALint size, numchans, numbits;
/* For each successfully unqueued buffer, increment the
* base time. */
alGetBufferi(buf, AL_SIZE, &size);
alGetBufferi(buf, AL_CHANNELS, &numchans);
alGetBufferi(buf, AL_BITS, &numbits);
basetime += size / numchans * 8 / numbits;
alBufferData(buf, format, data, count, rate);
alSourceQueueBuffers(source, 1, &buf);
alGetBufferi(buf, AL_SIZE, &size);
alGetBufferi(buf, AL_CHANNELS, &numchans);
alGetBufferi(buf, AL_BITS, &numbits);
filetime += size / numchans * 8 / numbits;
}
if(alGetError() != AL_NO_ERROR)
{
fprintf(stderr, " !!! Error buffering data !!!\n");
break;
}
}
}
fprintf(stderr, "\rTime: %ld:%05.02f\n", (long)(filetime/rate/60),
(float)(filetime%(rate*60))/(float)rate);
/* All done with this file. Close it and go to the next */
closeAVFile(file);
}
fprintf(stderr, "Done.\n");
if(!quitnow)
{
/* All data has been streamed in. Wait until the source stops playing it */
do {
Sleep(10);
alGetSourcei(source, AL_SOURCE_STATE, &state);
} while(alGetError() == AL_NO_ERROR && state == AL_PLAYING);
}
/* All files done. Delete the source and buffers, and close OpenAL */
free(data);
alDeleteSources(1, &source);
alDeleteBuffers(NUM_BUFFERS, buffers);
alcMakeContextCurrent(NULL);
alcDestroyContext(ctx);
alcCloseDevice(device);
return 0;
}
》bitmapparse.cpp 定义bmp对象操作类：
支持bmp文件头、bmp头和数据的信息提取、将data封装成bmp文件。
》FFMpegMedia ffmpeg最底层实现的基类class， 针对编解码和打开生成媒体文件对象，提供了系列基本ffmpeg方法：
初始化输入/出流，文件格式fmtCtx获取，获取/复制解码器codexCtx，
分配、读、解码pkt，包保存写入文件，frame类型判断，设置输入width,h,pixFmt等，
新建初始化aud/vid stream，打开、关闭ffmpeg api等。
》FFMpegVideo/Audio.cpp 是class FFMpegMedia的子类，扩充其。
只是提供了2个方法，将基类的virtual方法重构了下，如输出文件的ofmtCtx,oCodexCtx只带vid/aud专有信息，而不是basic class的公共信息。
》demux 定义FFMPegVideo class，针对文件对象，进行demux方法。
-->继承 FFMpegMedia basic class
》FFMpegAdapter 定义了几个公共方法。
RGBR/YUV Rotate90（）图片数据旋转90度，
av_create_bmp， RGBR数据buf，生成bmp文件；
video_to_picture()/ picture_to_video()： 图片和视频文件的互相生成。
》FFMpegUtil 定义了static公共方法，
视频生成n张图片，
ffmpeg注册释放api，文件中查找类型流ID，codeId Guess,打开/关闭xxCtx,
audio，查找、选择sapleRate,channelLayout方法。
》FFMpegOperation 通过调用上面的类，对音视频，图片文件进行操作；
提供了音视频分离/合并，视频生成n张图片，图片格式互转(bmp/jpg,png)方法。
其中ConvertImage方法，支持任意图片格式互转；其原理是调用FFMpegMedia 基类对输入输出PIC进行解码编码，输出cdexCtx是根据文件名后缀,调用FFMpegParseImage 子类的saveFrame重构方法，保存解码文件。
》FFMpegImage, 继承FFMPegVideo class，对图片进行读写转码操作；
重构了基类viturl 方法： 初始化/设置codexCtx, Read/SaveFrame根据img特性实现；
》