NDK r21编译FFmpeg 4.2.2+x264及使用ffmpeg转换视频文件

1.编译ffmpeg+x264

使用Ubuntu编译。以aarch64为例。

下载x264，进行编译。

#!/bin/bash

NDK=/home/qwe/android-ndk-r21
export TOOLCHAIN=$NDK/toolchains/llvm/prebuilt/linux-x86_64
export TARGET=aarch64-linux-android
export API=21

export AR=$TOOLCHAIN/bin/aarch64-linux-android-ar
#export AS=$TOOLCHAIN/bin/arm-linux-androideabi-as
export CC=$TOOLCHAIN/bin/$TARGET$API-clang
export CXX=$TOOLCHAIN/bin/$TARGET$API-clang++
export LD=$TOOLCHAIN/bin/aarch64-linux-android-ld
export RANLIB=$TOOLCHAIN/bin/aarch64-linux-android-ranlib
export STRIP=$TOOLCHAIN/bin/aarch64-linux-android-strip


function build_one
{
     
echo 'start' $kind
./configure \
    --enable-shared \
    --enable-pic \
    --host=$my_host \
    --sysroot=$NDK/toolchains/llvm/prebuilt/linux-x86_64/sysroot \
    --libdir=$libpath

make clean
make
make install
echo 'end' $kind
}

#aarch64
kind=aarch64
my_host=aarch64-linux-android
libpath=/usr/local/lib/x264/$kind
build_one

得到文件

编译ffmpeg+x264

#!/bin/bash
NDK=/home/qwe/android-ndk-r21
HOST_TAG=linux-x86_64
TOOLCHAIN=$NDK/toolchains/llvm/prebuilt/$HOST_TAG
AR=$TOOLCHAIN/bin/aarch64-linux-android-ar
AS=$TOOLCHAIN/bin/aarch64-linux-android-as
CC=$TOOLCHAIN/bin/aarch64-linux-android21-clang
CXX=$TOOLCHAIN/bin/aarch64-linux-android21-clang++
LD=$TOOLCHAIN/bin/aarch64-linux-android-ld
RANLIB=$TOOLCHAIN/bin/aarch64-linux-android-ranlib
STRIP=$TOOLCHAIN/bin/aarch64-linux-android-strip
NM=$TOOLCHAIN/bin/aarch64-linux-android-nm

#arm64  x86 x86_64 对应 aarch64  i686  x86_64 

PREFIX=./SO/aarch64


function build
{
     

./configure \
--prefix=$PREFIX \
--disable-static \
--enable-shared \
--enable-small \
--enable-gpl \
--enable-version3 \
--enable-pic \
--disable-doc \
--enable-asm \
--enable-cross-compile \
--target-os=android \
--arch=aarch64 \
--cc=$CC \
--ar=$AR \
--cxx=$CXX \
--ranlib=$RANLIB \
--strip=$STRIP \
--nm=$NM \
--sysroot=/home/qwe/android-ndk-r21/toolchains/llvm/prebuilt/linux-x86_64/sysroot \
--enable-libx264 \
--extra-cflags="-I/usr/local/include" \
--extra-ldflags="-L/usr/local/lib/x264/aarch64" 

make clean
make -j4
make install

}

build

编译完成

使用

运行

2.使用ffmpeg api转换视频格式

c/c++代码

#include 
#include 

extern "C" {
     
#include "libavcodec/avcodec.h"
#include "libavutil/timestamp.h"
#include "libavformat/avformat.h"
#include "libavutil/mathematics.h"
}

//代码来自ffmpeg demo中的代码remuxing.c
static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt, const char *tag) {
     
    AVRational *time_base = &fmt_ctx->streams[pkt->stream_index]->time_base;
    printf("%s: pts:%s pts_time:%s dts:%s dts_time:%s duration:%s duration_time:%s stream_index:%d\n",
           tag,
           av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, time_base),
           av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, time_base),
           av_ts2str(pkt->duration), av_ts2timestr(pkt->duration, time_base),
           pkt->stream_index);
}

//代码来自ffmpeg demo中的代码remuxing.c
extern "C"
int main(int argc, char **argv) {
     
    AVOutputFormat *ofmt = NULL;
    AVFormatContext *ifmt_ctx = NULL, *ofmt_ctx = NULL;
    AVPacket pkt;
    const char *in_filename, *out_filename;
    int ret, i;
    int stream_index = 0;
    int *stream_mapping = NULL;
    int stream_mapping_size = 0;
    if (argc < 3) {
     
        printf("usage: %s input output\n"
               "API example program to remux a media file with libavformat and libavcodec.\n"
               "The output format is guessed according to the file extension.\n"
               "\n", argv[0]);
        return 1;
    }
    in_filename = argv[1];
    out_filename = argv[2];
    if ((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, 0)) < 0) {
     
        fprintf(stderr, "Could not open input file '%s'", in_filename);
        goto end;
    }
    if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0) {
     
        fprintf(stderr, "Failed to retrieve input stream information");
        goto end;
    }
    av_dump_format(ifmt_ctx, 0, in_filename, 0);
    avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, out_filename);
    if (!ofmt_ctx) {
     
        fprintf(stderr, "Could not create output context\n");
        ret = AVERROR_UNKNOWN;
        goto end;
    }
    stream_mapping_size = ifmt_ctx->nb_streams;
    stream_mapping = (int *) av_mallocz_array(stream_mapping_size, sizeof(*stream_mapping));
    if (!stream_mapping) {
     
        ret = AVERROR(ENOMEM);
        goto end;
    }
    ofmt = ofmt_ctx->oformat;
    for (i = 0; i < ifmt_ctx->nb_streams; i++) {
     
        AVStream *out_stream;
        AVStream *in_stream = ifmt_ctx->streams[i];
        AVCodecParameters *in_codecpar = in_stream->codecpar;
        if (in_codecpar->codec_type != AVMEDIA_TYPE_AUDIO &&
            in_codecpar->codec_type != AVMEDIA_TYPE_VIDEO &&
            in_codecpar->codec_type != AVMEDIA_TYPE_SUBTITLE) {
     
            stream_mapping[i] = -1;
            continue;
        }
        stream_mapping[i] = stream_index++;
        out_stream = avformat_new_stream(ofmt_ctx, NULL);
        if (!out_stream) {
     
            fprintf(stderr, "Failed allocating output stream\n");
            ret = AVERROR_UNKNOWN;
            goto end;
        }
        ret = avcodec_parameters_copy(out_stream->codecpar, in_codecpar);
        if (ret < 0) {
     
            fprintf(stderr, "Failed to copy codec parameters\n");
            goto end;
        }
        out_stream->codecpar->codec_tag = 0;
    }
    av_dump_format(ofmt_ctx, 0, out_filename, 1);
    if (!(ofmt->flags & AVFMT_NOFILE)) {
     
        ret = avio_open(&ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE);
        if (ret < 0) {
     
            fprintf(stderr, "Could not open output file '%s'", out_filename);
            goto end;
        }
    }
    ret = avformat_write_header(ofmt_ctx, NULL);
    if (ret < 0) {
     
        fprintf(stderr, "Error occurred when opening output file\n");
        goto end;
    }
    while (1) {
     
        AVStream *in_stream, *out_stream;
        ret = av_read_frame(ifmt_ctx, &pkt);
        if (ret < 0)
            break;
        in_stream = ifmt_ctx->streams[pkt.stream_index];
        if (pkt.stream_index >= stream_mapping_size ||
            stream_mapping[pkt.stream_index] < 0) {
     
            av_packet_unref(&pkt);
            continue;
        }
        pkt.stream_index = stream_mapping[pkt.stream_index];
        out_stream = ofmt_ctx->streams[pkt.stream_index];
        log_packet(ifmt_ctx, &pkt, "in");
/* copy packet */
        pkt.pts = av_rescale_q_rnd(pkt.pts, in_stream->time_base, out_stream->time_base,
                                   (AVRounding)(AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX));
        pkt.dts = av_rescale_q_rnd(pkt.dts, in_stream->time_base, out_stream->time_base,
                                   (AVRounding)(AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX));
        pkt.duration = av_rescale_q(pkt.duration, in_stream->time_base, out_stream->time_base);
        pkt.pos = -1;
        log_packet(ofmt_ctx, &pkt, "out");
        ret = av_interleaved_write_frame(ofmt_ctx, &pkt);
        if (ret < 0) {
     
            fprintf(stderr, "Error muxing packet\n");
            break;
        }
        av_packet_unref(&pkt);
    }
    av_write_trailer(ofmt_ctx);
    end:
    avformat_close_input(&ifmt_ctx);
/* close output */
    if (ofmt_ctx && !(ofmt->flags & AVFMT_NOFILE))
        avio_closep(&ofmt_ctx->pb);
    avformat_free_context(ofmt_ctx);
    av_freep(&stream_mapping);
    if (ret < 0 && ret != AVERROR_EOF) {
     
        fprintf(stderr, "Error occurred: %s\n", av_err2str(ret));
        return 1;
    }
    return 0;
}

extern "C"
JNIEXPORT jint JNICALL
Java_cn_study_testffmpeg_MainActivity_execute(JNIEnv *env, jobject thiz, jobjectArray commands) {
     

    int argc = env->GetArrayLength(commands);
    char *argv[argc];

    int i;
    for (i = 0; i < argc; i++) {
     
        jstring js = (jstring) env->GetObjectArrayElement(commands, i);
        argv[i] = (char *) env->GetStringUTFChars(js, 0);
    }

    return main(argc, argv);
}

java代码

        String a = Environment.getExternalStorageDirectory().getAbsolutePath();

        String cmd = "ffmpeg " + a + "/video.mp4 " + a + "/output.flv";

        File file = new File(a, "output.flv");
        try {
     
            file.createNewFile();
        } catch (IOException e) {
     
            e.printStackTrace();
        }
        
        String[] commands = cmd.split("\\s+");
        int asd = execute(commands);

效果