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• ffmpeg API muxing h264 endoced frames to mkv

  24 mars 2017, par Pawel K

  Hi I’m having some problems with muxing h264 encoded frames into mkv container using code of ffmpeg-3.2.4.
  I have ended up with the following code that is a mashup of code found on SO and muxing.c example of ffmpeg :
  (and yes I am aware that it is ugly, no errors checked etc. it is meant to be like that for clarity :) )

  char *filename = "out.mkv";
  
  const uint8_t SPS[] = { 0x67, 0x42, 0x40, 0x1F, 0x96, 0x54, 0x02, 0x80, 0x2D, 0xD0, 0x0F, 0x39, 0xEA };
  
  const uint8_t PPS[] = { 0x68, 0xCE, 0x38, 0x80 };
  
  int fps = 5;
  
  
  
  typedef struct OutputStream
  
  {
  
     AVStream *st;
  
     AVCodecContext *enc;
  
  
  
     /* pts of the next frame that will be generated */
  
     int64_t next_pts;
  
     int samples_count;
  
     AVFrame *frame;
  
     AVFrame *tmp_frame;
  
     float t, tincr, tincr2;
  
     struct SwsContext *sws_ctx;
  
     struct SwrContext *swr_ctx;
  
  } OutputStream;
  
  
  
  static void avlog_cb(void *s, int level, const char *szFmt, va_list varg)
  
  {
  
     vprintf(szFmt, varg);
  
  }
  
  
  
  void main()
  
  {
  
     AVOutputFormat *fmt;
  
     AVFormatContext *formatCtx;
  
     AVCodec *audio_codec;
  
     AVCodec *video_codec;
  
     OutputStream video_st = { 0 };
  
     OutputStream audio_st = { 0 };
  
     av_register_all();
  
  
  
     av_log_set_level(AV_LOG_TRACE);
  
     //av_log_set_callback(avlog_cb);
  
  
  
     //allocate output and format ctxs
  
     avformat_alloc_output_context2(&formatCtx, NULL, NULL, filename);
  
     fmt = formatCtx->oformat;
  
  
  
     //allocate streams
  
     video_codec = avcodec_find_encoder(fmt->video_codec);
  
     video_st.st = avformat_new_stream(formatCtx, NULL);
  
     video_st.st->id = 0;
  
  
  
     AVCodecContext *codecCtx =  avcodec_alloc_context3(video_codec);
  
     fmt->video_codec = AV_CODEC_ID_H264;
  
     video_st.enc = codecCtx;
  
  
  
     codecCtx->codec_id = fmt->video_codec;
  
     codecCtx->bit_rate = 400000;
  
     codecCtx->width  = 1080;
  
     codecCtx->height = 720;
  
     codecCtx->profile = FF_PROFILE_H264_CONSTRAINED_BASELINE;
  
     codecCtx->level = 31;
  
  
  
     video_st.st->time_base = (AVRational){ 1, fps };
  
     codecCtx->time_base = video_st.st->time_base;
  
     codecCtx->gop_size = 4;
  
     codecCtx->pix_fmt = AV_PIX_FMT_YUV420P;
  
  
  
     //open video codec
  
     codecCtx->extradata_size = 24;
  
     codecCtx->extradata = (uint8_t *)av_malloc(codecCtx->extradata_size);
  
     uint8_t extra_data_array[] = { 0x01, SPS[1], SPS[2], SPS[3], 0xFF, 0xE1, 0xc0, 0, 0x42, 0x40, 0x1F, 0x96, 0x54, 0x02, 0x80, 0x2D, 0xD0, 0x0F, 0x39, 0xEA, 0x03, 0xCE, 0x38, 0x80 };
  
     memcpy(codecCtx->extradata, extra_data_array, codecCtx->extradata_size);
  
  
  
     AVCodecContext *c = video_st.enc;
  
     AVDictionary *opt = NULL;
  
     avcodec_open2(c, video_codec, &opt);
  
     avcodec_parameters_from_context(video_st.st->codecpar, c);
  
  
  
     //open output file
  
     avio_open(&formatCtx->pb, filename, AVIO_FLAG_WRITE);
  
  
  
     //write header
  
     int res = avformat_write_header(formatCtx, NULL);
  
  
  
     //write frames
  
  
  
     // get the frames from file
  
     uint32_t u32frameCnt = 0;
  
  
  
     do
  
     {
  
        int8_t i8frame_name[64] = "";
  
  
  
        uint8_t  *pu8framePtr = NULL;
  
        AVPacket pkt = { 0 };
  
  
  
        av_init_packet(&pkt);
  
        sprintf(i8frame_name, "frames/frame%d.bin", u32frameCnt++);
  
        //reading frames from files
  
        FILE *ph264Frame = fopen(i8frame_name, "r");
  
        if(NULL == ph264Frame)
  
        {
  
           goto leave;
  
        }
  
  
  
        //get file size
  
        fseek(ph264Frame, 0L, SEEK_END);
  
        uint32_t u32file_size = 0;
  
        u32file_size = ftell(ph264Frame);
  
        fseek(ph264Frame, 0L, SEEK_SET);
  
  
  
        pu8framePtr = malloc(u32file_size);
  
        uint32_t u32readout = fread(pu8framePtr, 1, u32file_size, ph264Frame);
  
  
  
        //if the read frame is a key frame i.e. nalu hdr type = 5 set it as a key frame
  
        if(0x65 == pu8framePtr[4])
  
        {
  
           pkt.flags = AV_PKT_FLAG_KEY;
  
        }
  
        pkt.data = (uint8_t *)pu8framePtr;
  
        pkt.size = u32readout;
  
        pkt.pts  = u32frameCnt;
  
        pkt.dts  = pkt.pts;
  
  
  
        av_packet_rescale_ts(&pkt, c->time_base, video_st.st->time_base);
  
        pkt.stream_index = video_st.st->index;
  
        av_interleaved_write_frame(formatCtx, &pkt);
  
        free(pu8framePtr);
  
        fclose(ph264Frame);
  
     }
  
     while(1);
  
  leave:
  
  
  
     av_write_trailer(formatCtx);
  
     av_dump_format(formatCtx, 0, filename, 1);
  
     avcodec_free_context(&video_st.enc);
  
     avio_closep(&formatCtx->pb);
  
     avformat_free_context(formatCtx);
  
  }

  It can be compiled with the following command line (after adding headers) :

  gcc file.c -o test_app -I/usr/local/include -L/usr/local/lib -lxcb-shm -lxcb -lX11 -lx264 -lm -lz -pthread -lswresample -lswscale -lavcodec -lavformat -lavdevice -lavutil

  The files that are read are valid annexB stream (valid as in it’s playable in vlc after concatenating into file) it is a Constrained Baseline 3.1 profile H264 and it comes from an IPcam’s interleaved RTCP/RTP stream (demuxed)

  The result is ... well I don’t see the picture. I get only black screen with the progress bar and timer running. I don’t know if I do something wrong with setting up the codecs and streams, or it’s just wrong timestamps.
  I know I got them wrong in some manner but I don’t understand that fully yet (how to calculate the correct presentation times), i.e. the stream and the codec both contain time_base field, and then I know that the sample rate of the video is 90kHz and the frame rate is 5 fps

  On top of it all the examples I’ve found have to some extend deprecated parts that change the flow/meaning of the application and that doesn’t help at all so thus If anyone could help I would appreciate it (I think not only me I would guess)

  Regards, Pawel

• Encoding RGB frames using x264 and AVCodec in C

  6 novembre 2016, par deepwork

  I have RGB24 frames streamed from camera and i want to encode them into h264 ,i found that AVCodec and x264 can do so, the problem is x264 as default accepts YUV420 as input so what i wrote was a program which convert RGB frames to YUV420 .that was by sws_scale function .this works well except that it does not satisfy the required FPS because the converting (RGB->YUV420) takes time.

  This is how i setup my encoder context :

  videoStream->id = 0;
  
  vCodecCtx = videoStream->codec;
  
  
  
  vCodecCtx->coder_type       = AVMEDIA_TYPE_VIDEO;
  
  vCodecCtx->codec_id         = AV_CODEC_ID_H264;
  
  vCodecCtx->bit_rate         = 400000;
  
  vCodecCtx->width            = Width;
  
  vCodecCtx->height           = Height;
  
  vCodecCtx->time_base.den    = FPS;
  
  vCodecCtx->time_base.num    = 1;
  
  //vCodecCtx->time_base      = (AVRational){1,};
  
  vCodecCtx->gop_size         = 12;
  
  vCodecCtx->max_b_frames     = 1;
  
  vCodecCtx->pix_fmt          = AV_PIX_FMT_YUV420P;
  
  
  
  if(formatCtx->oformat->flags & AVFMT_GLOBALHEADER)
  
      vCodecCtx->flags |= CODEC_FLAG_GLOBAL_HEADER;
  
  
  
  av_opt_set(vCodecCtx->priv_data, "preset", "ultrafast", 0);
  
  av_opt_set(vCodecCtx->priv_data, "profile", "baseline", AV_OPT_SEARCH_CHILDREN);
  
  
  
  if (avcodec_open2(vCodecCtx, h264Codec, NULL) < 0){
  
      return 0;
  
  }

  when i changes AV_PIX_FMT_YUV420P to AV_PIX_FMT_RGB24 ,avcodec_open2 will fail.
  i read that there is a version of libx264 for RGB called libx264rgb but i even dont know whether i have to rebuild x264 with enabling this option or to download another source or i have to do it programmatically with the first x264 lib.

  the question is how to enable RGB as input to libx264 to use with libavcodec in C .or how to make the encoding or sws_scale more fast .

  Edit :

  How i built ffmpeg :

  NDK=D:/AndroidDev/android-ndk-r9
  
  PLATFORM=$NDK/platforms/android-18/arch-arm/
  
  PREBUILT=$NDK/toolchains/arm-linux-androideabi-4.8/prebuilt/windows-x86_64
  
  
  
  GENERAL="\
  
  --enable-small \
  
  --enable-cross-compile \
  
  --extra-libs="-lgcc" \
  
  --arch=arm \
  
  --cc=$PREBUILT/bin/arm-linux-androideabi-gcc \
  
  --cross-prefix=$PREBUILT/bin/arm-linux-androideabi- \
  
  --nm=$PREBUILT/bin/arm-linux-androideabi-nm \
  
  --extra-cflags="-I../x264/android/arm/include" \
  
  --extra-ldflags="-L../x264/android/arm/lib" "
  
  
  
  
  
  MODULES="\
  
  --enable-gpl \
  
  --enable-libx264"
  
  
  
  function build_ARMv6
  
  {
  
    ./configure \
  
    --target-os=linux \
  
    --prefix=./android/armeabi \
  
    ${GENERAL} \
  
    --sysroot=$PLATFORM \
  
    --enable-shared \
  
    --disable-static \
  
    --extra-cflags=" -O3 -fpic -fasm -Wno-psabi -fno-short-enums -fno-strict-aliasing -finline-limit=300 -mfloat-abi=softfp -mfpu=vfp -marm -march=armv6" \
  
    --extra-ldflags="-lx264 -Wl,-rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib -nostdlib -lc -lm -ldl -llog" \
  
    --enable-zlib \
  
    ${MODULES} \
  
    --disable-doc \
  
    --enable-neon
  
  
  
    make clean
  
    make
  
    make install
  
  }
  
  
  
  build_ARMv6
  
  
  
  echo Android ARMEABI builds finished

  How i built x264 :

  NDK=D:/AndroidDev/android-ndk-r9
  
  PLATFORM=$NDK/platforms/android-18/arch-arm/
  
  TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.8/prebuilt/windows-x86_64
  
  PREFIX=./android/arm
  
  
  
  function build_one
  
  {
  
    ./configure \
  
    --prefix=$PREFIX \
  
    --enable-static \
  
    --enable-pic \
  
    --host=arm-linux \
  
    --cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
  
    --sysroot=$PLATFORM
  
  
  
    make clean
  
    make
  
    make install
  
  }
  
  
  
  build_one
  
  
  
  echo Android ARM builds finished

• duration change after transcode ts

  25 décembre 2017, par Feilong Luo

  i have a problem about transcode with ffmpeg

  i want to cover m3u8 to mp4, so i transcode every ts file first, and then concat them to a mp4, but i found that the duration will be bigger than source file.

  source file is :
  http://oc7iy3eta.bkt.clouddn.com/src_20.ts

  after transcode, test file is :
  http://oc7iy3eta.bkt.clouddn.com/test_20.ts

  i use the command as bellow to change to 5fps, and 400k bitrate :

  sudo ffmpeg -analyzeduration 2147483647 -probesize 2147483647 -nostdin -y -v warning -i ./src_20.ts -threads 3 -movflags faststart -metadata:s:v rotate=0 -chunk_duration 520000 -video_track_timescale 25000 -pix_fmt yuv420p -copytb 1 -vcodec libx264 -b:v 400000 -minrate 400000 -maxrate 400000 -bufsize 500k -force_key_frames "expr:gte(t,n_forced*2)" -vsync 1 -r 5 -s 544*960 -acodec libfaac -async 1 ./test_20.ts

  i use ffprobe command to see video info :

  source file info :

  Duration : 00:00:01.26, start : 28.346989, bitrate : 921 kb/s
  Program 1
  Metadata :
  service_name : Service01
  service_provider : FFmpeg
  Stream #0:0[0x100] : Audio : aac ([15][0][0][0] / 0x000F), 44100 Hz, stereo, fltp, 23 kb/s
  Stream #0:1[0x101] : Video : h264 (High) ([27][0][0][0] / 0x001B), yuv420p, 544x960, 10.67 tbr, 90k tbn, 180k tbc

  test file :

  Input #0, mpegts, from ’test_20.ts’ :
  Duration : 00:00:01.62, start : 1.576778, bitrate : 447 kb/s
  Program 1
  Metadata :
  service_name : Service01
  service_provider : FFmpeg
  Stream #0:0[0x100] : Video : h264 (High) ([27][0][0][0] / 0x001B), yuv420p, 544x960, 5 fps, 5 tbr, 90k tbn, 10 tbc
  Stream #0:1[0x101] : Audio : aac ([15][0][0][0] / 0x000F), 44100 Hz, stereo, fltp, 5 kb/s

  =======================================================================

  question

  so , we can see that the duration of src file is 1.26s , but after transcode, the test file is 1.62s.

  why ? can anybody help