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• Encoding to h264 failed to send some frames using ffmpeg c api

  8 juillet 2020, par Vuwox

  Using FFMPEG C API, Im trying to push generated image to MP4 format.

  


  When I push frame-by-frame, the muxing seems to failed on avcodec_receive_packet(...) which return AVERROR(EAGAIN) on the first frames, but after a while is starting to add my frame, but the first one.

  


  What I mean, is that when push frame 1 to 13, I have errors, but after frame 14 to end (36), the frame are added to the video, but the encoded image are not the 14 to 36, instead its the frame 1 to 23 that are added.

  


  I don't understand, is this a problem with the framerate (which i want 12 fps), or with key/inter- frame ?

  


  Here the code for different part of the class,

  


  NOTE :

  


  

  • m_filename = "C :\tmp\test.mp4"

  


  • m_framerate = 12

  


  • m_width = 1080

  


  • m_height = 1080

  


  


  ctor

  


  // Allocate the temporary buffer that hold the our generated image in RGB.
picture_rgb24 = av_frame_alloc();
picture_rgb24->pts = 0;
picture_rgb24->data[0] = NULL;
picture_rgb24->linesize[0] = -1;
picture_rgb24->format = AV_PIX_FMT_RGB24;
picture_rgb24->height = m_height;
picture_rgb24->width = m_width;

if ((_ret = av_image_alloc(picture_rgb24->data, picture_rgb24->linesize, m_width, m_height, (AVPixelFormat)picture_rgb24->format, 24)) < 0)
    throw ...

// Allocate the temporary frame that will be convert from RGB to YUV using ffmpeg api.
frame_yuv420 = av_frame_alloc();
frame_yuv420->pts = 0;
frame_yuv420->data[0] = NULL;
frame_yuv420->linesize[0] = -1;
frame_yuv420->format = AV_PIX_FMT_YUV420P;
frame_yuv420->width = m_height;
frame_yuv420->height = m_width;

if ((_ret = av_image_alloc(frame_yuv420->data, frame_yuv420->linesize, m_width, m_height, (AVPixelFormat)frame_yuv420->format, 32)) < 0)
    throw ...

init_muxer(); // see below.

m_inited = true;
    
m_pts_increment = av_rescale_q(1, { 1, m_framerate }, ofmt_ctx->streams[0]->time_base);

// Context that convert the RGB24 to YUV420P format (using this instead of filter similar to GIF).
swsCtx = sws_getContext(m_width, m_height, AV_PIX_FMT_RGB24, m_width, m_height, AV_PIX_FMT_YUV420P, SWS_BICUBIC, 0, 0, 0);


  


  init_muxer :

  


  AVOutputFormat* oformat = av_guess_format(nullptr, m_filename.c_str(), nullptr);
if (!oformat) throw ...

_ret = avformat_alloc_output_context2(&ofmt_ctx, oformat, nullptr, m_filename.c_str());
if (_ret) throw ...

AVCodec *codec = avcodec_find_encoder(oformat->video_codec);
if (!codec) throw ...

AVStream *stream = avformat_new_stream(ofmt_ctx, codec);
if (!stream) throw ...

o_codec_ctx = avcodec_alloc_context3(codec);
if (!o_codec_ctx) throw ...

stream->codecpar->codec_id = oformat->video_codec;
stream->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
stream->codecpar->width = m_width;
stream->codecpar->height = m_height;
stream->codecpar->format = AV_PIX_FMT_YUV420P;
stream->codecpar->bit_rate = 400000;

avcodec_parameters_to_context(o_codec_ctx, stream->codecpar);
o_codec_ctx->time_base = { 1, m_framerate };

// Using gop_size == 0, we want 'intra' frame, so no b-frame will be generated.
o_codec_ctx->max_b_frames = 0;
o_codec_ctx->gop_size = 0;
o_codec_ctx->b_quant_offset = 0;
//o_codec_ctx->framerate = { m_framerate , 1 };

if (stream->codecpar->codec_id == AV_CODEC_ID_H264)
    av_opt_set(o_codec_ctx, "preset", "ultrafast", 0);      // Lossless H.264
else if (stream->codecpar->codec_id == AV_CODEC_ID_H265)
    av_opt_set(o_codec_ctx, "preset", "ultrafast", 0);      // Lossless H.265

avcodec_parameters_from_context(stream->codecpar, o_codec_ctx);

if ((_ret = avcodec_open2(o_codec_ctx, codec, NULL)) < 0)
    throw ...

if ((_ret = avio_open(&ofmt_ctx->pb, m_filename.c_str(), AVIO_FLAG_WRITE)) < 0)
    throw ...

if ((_ret = avformat_write_header(ofmt_ctx, NULL)) < 0)
    throw ...

av_dump_format(ofmt_ctx, 0, m_filename.c_str(), 1);


  


  add_frame :

  


  // loop to transfer our image format to ffmpeg one.
for (int y = 0; y < m_height; y++)
{
    for (int x = 0; x < m_width; x++)
    {
        picture_rgb24->data[0][idx] = ...;
        picture_rgb24->data[0][idx + 1] = ...;
        picture_rgb24->data[0][idx + 2] = ...;
    }
}

// From RGB to YUV
sws_scale(swsCtx, (const uint8_t * const *)picture_rgb24->data, picture_rgb24->linesize, 0, m_height, frame_yuv420->data, frame_yuv420->linesize);

// mux the YUV frame
muxing_one_frame(frame_yuv420);

// Increment the FPS of the picture for the next add-up to the buffer.      
picture_rgb24->pts += m_pts_increment;
frame_yuv420->pts += m_pts_increment;


  


  muxing_one_frame :

  


  int ret = avcodec_send_frame(o_codec_ctx, frame);
AVPacket *pkt = av_packet_alloc();
av_init_packet(pkt);

while (ret >= 0) {
    ret = avcodec_receive_packet(o_codec_ctx, pkt);
    if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) break;        
    av_write_frame(ofmt_ctx, pkt);
}
av_packet_unref(pkt);


  


  close_file :

  


  av_write_trailer(ofmt_ctx);
avio_close(ofmt_ctx->pb);


  


• ffmpeg : LIVE HLS Playback getting delayed over time

  31 juillet 2020, par Krishnakumar

  We are converting UDP Input to Live HLS output and pushing the chunks to a webdav server. Initial playback works fine, But the playback was delayed by almost an hour, when we checked after 15 hours. Not sure this is caused due to network as we use internet to push the chunks. Below is the ffmpeg command used.

  


  ffmpeg -i udp://230.1.1.15:10000?fifo_size=10000000&overrun_nonfatal=1 -filter_complex [i:0xd49]yadif,setdar=256/144[v0];[i:0xd49]yadif,setdar=512/288[v1];[i:0xd49]yadif,setdar=640/360[v2];[i:0xd49]yadif,setdar=1280/720[v3] -f hls -map i:0xd4a -af aresample=async=1:min_hard_comp=0.100000:first_pts=0 -c:a:0 libfdk_aac -b:a:0 48000 -ar:0 48000 -map [v0] -b:v:0 100000 -maxrate:v:0 100000 -minrate:v:0 100000 -bufsize:v:0 200000 -s:v:0 256x144 -r:0 25 -sc_threshold 0 -pix_fmt yuv420p -flags +global_header+cgop -c:v:0 libx264 -profile:v:0 baseline -level:v:0 3.0 -preset:v:0 fast -nal-hrd cbr -g 50 -map i:0xd4a -af aresample=async=1:min_hard_comp=0.100000:first_pts=0 -c:a:1 libfdk_aac -b:a:1 48000 -ar:1 48000 -map [v1] -b:v:1 200000 -maxrate:v:1 200000 -minrate:v:1 200000 -bufsize:v:1 400000 -s:v:1 512x288 -r:1 25 -sc_threshold 0 -pix_fmt yuv420p -flags +global_header+cgop -c:v:1 libx264 -profile:v:1 baseline -level:v:1 3.0 -preset:v:1 fast -nal-hrd cbr -g 50 -map i:0xd4a -af aresample=async=1:min_hard_comp=0.100000:first_pts=0 -c:a:2 libfdk_aac -b:a:2 64000 -ar:2 48000 -map [v2] -b:v:2 700000 -maxrate:v:2 700000 -minrate:v:2 700000 -bufsize:v:2 1400000 -s:v:2 640x360 -r:2 25 -sc_threshold 0 -pix_fmt yuv420p -flags +global_header+cgop -c:v:2 libx264 -profile:v:2 baseline -level:v:2 3.0 -preset:v:2 fast -nal-hrd cbr -g 50 -map i:0xd4a -af aresample=async=1:min_hard_comp=0.100000:first_pts=0 -c:a:3 libfdk_aac -b:a:3 64000 -ar:3 48000 -map [v3] -b:v:3 1000000 -maxrate:v:3 1000000 -minrate:v:3 1000000 -bufsize:v:3 2000000 -s:v:3 1280x720 -r:3 25 -sc_threshold 0 -pix_fmt yuv420p -flags +global_header+cgop -c:v:3 libx264 -profile:v:3 high -level:v:3 4.0 -preset:v:3 fast -nal-hrd cbr -g 50 -var_stream_map a:0,v:0,name:148k a:1,v:1,name:248k a:2,v:2,name:764k a:3,v:3,name:1064k -master_pl_name master.m3u8 -hls_list_size 3 -hls_time 6 -hls_segment_filename https://usr:pass@example.com:8043/httppush/media_%v_%03d.ts -hls_flags delete_segments+independent_segments+discont_start https://usr:pass@example.com:8043/httppush/playlist_%v.m3u8


  


  FFMPEG V4.3

  


  ffmpeg version 4.3 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 4.8.5 (GCC) 20150623 (Red Hat 4.8.5-36)
  configuration: --prefix=/root/ffmpeg_build --pkg-config-flags=--static --extra-cflags=-I/root/ffmpeg_build/include --extra-ldflags=-L/root/ffmpeg_build/lib --extra-libs=-lpthread --extra-libs=-lm --bindir=/root/bin --enable-gpl --enable-libfdk_aac --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-libvpx --enable-libx264 --enable-libx265 --enable-nonfree --enable-openssl
  libavutil      56. 51.100 / 56. 51.100
  libavcodec     58. 91.100 / 58. 91.100
  libavformat    58. 45.100 / 58. 45.100
  libavdevice    58. 10.100 / 58. 10.100
  libavfilter     7. 85.100 /  7. 85.100
  libswscale      5.  7.100 /  5.  7.100
  libswresample   3.  7.100 /  3.  7.100
  libpostproc    55.  7.100 / 55.  7.100


  


  With Split Filter :

  


  ffmpeg -i "udp://230.1.1.15:10000?fifo_size=10000000&overrun_nonfatal=1" -filter_complex "[i:0xd49]yadif[v];[v]split=4[1out1][1out2][1out3][1out4];[1out1]setdar=256/144[v0];[1out2]setdar=512/288[v1];[1out3]setdar=640/360[v2];[1out4]setdar=1280/720[v3];[i:0xd4a]aresample=async=1:min_hard_comp=0.100000:first_pts=0[a];[a]asplit=4[a0][a1][a2][a3]" -f hls -map [a0] -c:a:0 libfdk_aac -b:a:0 48000 -ar:0 48000 -map [v0] -b:v:0 100000 -maxrate:v:0 100000 -minrate:v:0 100000 -bufsize:v:0 200000 -s:v:0 256x144 -r:0 25 -sc_threshold 0 -pix_fmt yuv420p -flags +global_header+cgop -c:v:0 libx264 -profile:v:0 baseline -level:v:0 3.0 -preset:v:0 fast -nal-hrd cbr -g 50 -map [a1] -c:a:1 libfdk_aac -b:a:1 48000 -ar:1 48000 -map [v1] -b:v:1 200000 -maxrate:v:1 200000 -minrate:v:1 200000 -bufsize:v:1 400000 -s:v:1 512x288 -r:1 25 -sc_threshold 0 -pix_fmt yuv420p -flags +global_header+cgop -c:v:1 libx264 -profile:v:1 baseline -level:v:1 3.0 -preset:v:1 fast -nal-hrd cbr -g 50 -map [a2] -c:a:2 libfdk_aac -b:a:2 64000 -ar:2 48000 -map [v2] -b:v:2 700000 -maxrate:v:2 700000 -minrate:v:2 700000 -bufsize:v:2 1400000 -s:v:2 640x360 -r:2 25 -sc_threshold 0 -pix_fmt yuv420p -flags +global_header+cgop -c:v:2 libx264 -profile:v:2 baseline -level:v:2 3.0 -preset:v:2 fast -nal-hrd cbr -g 50 -map [a3] -c:a:3 libfdk_aac -b:a:3 64000 -ar:3 48000 -map [v3] -b:v:3 1000000 -maxrate:v:3 1000000 -minrate:v:3 1000000 -bufsize:v:3 2000000 -s:v:3 1280x720 -r:3 25 -sc_threshold 0 -pix_fmt yuv420p -flags +global_header+cgop -c:v:3 libx264 -profile:v:3 high -level:v:3 4.0 -preset:v:3 fast -nal-hrd cbr -g 50 -var_stream_map "a:0,v:0,name:148k a:1,v:1,name:248k a:2,v:2,name:764k a:3,v:3,name:1064k" -master_pl_name master.m3u8 -hls_list_size 3 -hls_time 6 -hls_segment_filename https://usr:pass@example.com:8043/httppush/media_%v_%03d.ts -hls_flags delete_segments+independent_segments+discont_start https://usr:pass@example.com:8043/httppush/playlist_%v.m3u8


  


• Ffmpeg inaccurate cut duration with ts [duplicate]

  30 juillet 2020, par Lemon Sky

  I need to accurately seek and cut a video. Some online sources say put -ss in front or after the source. The result is the same for me. In the examples below, the start time is accurate but the duration is not accurate.

  


  ffmpeg -y -ss 00:00:05 -t 00:00:05 -i http://tyberis.com/output.ts 5s.wav
ffprobe 5s.wav

Duration: 00:00:04.74

ffmpeg -y -i http://tyberis.com/output.ts -ss 00:00:05 -t 00:00:05 5s.wav
ffprobe 5s.wav

Duration: 00:00:04.74


  


  Sometimes the starting point is not accurate but the duration is. This is clearly audible by cutting the ts file and cutting an uncompressed wav file, and listening to both.

  


  ffmpeg -y -i http://tyberis.com/output.ts -ss 00:00:15 -t 00:00:05 5s.wav

ffmpeg -y -i http://tyberis.com/output.wav -ss 00:00:15 -t 00:00:05 5s-reference.wav


  


  What fixes the starting time is if I use an m3u8 file that contains the byte offset for every keyframe AND I put the -ss option in front of the source file (if I put it after the source, the start time is inaccurate but the duration is accurate) :

  


  ffmpeg -y -ss 00:00:15 -t 00:00:05 -i http://tyberis.com/output.m3u8 5s.wav


  


  This fixes the start time but the duration is at the location that I would get had I used no m3u8 file (duration is just 4.47s).

  


  It seems different timestamps are involved, and sometimes one or the other gets used.

  


  The ts file was generated by capturing a UDP stream and storing it with ffmpeg and -codec:v copy.

  


  Is ffmpeg broken, or the ts file ? How do I work around this issue or fix the ts file ? What I realize is that the video starts later than the audio, probably because the video does not start with a keyframe. Can I get ffmpeg to start the -codec:v copy after the first keyframe ? What I also notice is that using ffprobe reports "start : 1.400000". Can I force it to start at 0 ?

  


  Any hints would be appreciated.

  


  I tried both ffmpeg 4.3.1 and ffmpeg git-2020-07-24-21442a8.