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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);


  


• Transcode HLS segments individually with FFMPEG

  9 juillet 2020, par Mathix420

  I'm trying to transcode a video in HLS, by first splitting the video in segments without encoding changes and then transcode all segments individually. I'm trying to achieve this so I can transcode a video in multiple EC2 instances in parallel to be more time efficient.

  


  I am using this scipt right now

  


  # Split input file in multiple segments

ffmpeg -hide_banner -y -i $input -c copy -map 0 -an -segment_time 4 -reset_timestamps 1 -f segment output%03d.webm

# Transcode each segments in multiple resolutions

find . -name 'output*.webm' -exec ffmpeg -hide_banner -y -i {} \
  -vf "scale=-2:360" -c:v libx264 -profile:v main -crf 20 -sc_threshold 0 -b:v 800k -maxrate 856k -bufsize 1200k {}.360p.ts \
  -vf "scale=-2:480" -c:v libx264 -profile:v main -crf 20 -sc_threshold 0 -b:v 1400k -maxrate 1498k -bufsize 2100k {}.480p.ts \
  -vf "scale=-2:720" -c:v libx264 -profile:v main -crf 20 -sc_threshold 0 -b:v 2800k -maxrate 2996k -bufsize 4200k {}.720p.ts \
  -vf "scale=-2:1080" -c:v libx264 -profile:v main -crf 20 -sc_threshold 0 -b:v 5000k -maxrate 5350k -bufsize 7500k {}.1080p.ts \;


  


  But then when I tried to get all segments durations to make an m3u8 playlist (with the command below)

  


  # List segments duration

find . -name 'output*.webm.360p.ts' \
  -exec echo -n {} \; \
  -exec ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 {} \;


  


  I got this result

  


  output000.webm.360p.ts 5.120000
output001.webm.360p.ts 5.120000
output002.webm.360p.ts 4.400000
output003.webm.360p.ts 5.480000
output004.webm.360p.ts 0.360000
output005.webm.360p.ts 5.120000
output006.webm.360p.ts 4.960000
output007.webm.360p.ts 0.001000


  


  I can't figure out why my output004 is only 0.360000 seconds long.

  


  When I tried to play it with VLC it just shows one or two frames then main decoder error: buffer deadlock prevented.

  


  Thanks for trying to help me !

  


• I want to get the data of the MPEG2ts data stream

  26 juin 2020, par 夏目たかし

  I want to get the data of the MPEG2ts data stream using FFMPEG.

  


  Delivery side :

  


  ffmpeg -re -i hoge.ts -map 0 -c copy -f mpegts udp://127.0.0.1:5004


  


  Receiver :

  


  ffmpeg -i udp://127.0.0.1:5004 -map 0:1 -codec copy -f data stream.txt


  


  I started two command prompts and both were running on one PC.

  


  disp Delivery side message :

  


  Input #0, mpegts, from 'E:/Day_Flight.mpg':
  Duration: 00:03:14.88, start: 10.000000, bitrate: 4187 kb/s
  Program 1
    Stream #0:0[0x1e1]: Video: h264 (Main) ([27][0][0][0] / 0x001B), 
yuv420p(progressive), 1280x720, 60 fps, 60 tbr, 90k tbn, 180k tbc
    Stream #0:1[0x1f1]: Data: klv (KLVA / 0x41564C4B)
Output #0, mpegts, to 'udp://127.0.0.1:5004':
  Metadata:
    encoder         : Lavf58.47.100
    Stream #0:0: Video: h264 (Main) ([27][0][0][0] / 0x001B), yuv420p(progressive), 1280x720, q=2-31, 60 fps, 60 tbr, 90k tbn, 90k tbc
    Stream #0:1: Data: klv (KLVA / 0x41564C4B)
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #0:1 -> #0:1 (copy)


  


  disp Receiver message :

  


  Input #0, mpegts, from 'udp://127.0.0.1:5004':
  Duration: N/A, start: 1.400000, bitrate: N/A
  Program 1
    Metadata:
      service_name    : Service01
      service_provider: FFmpeg
    Stream #0:0[0x100]: Video: h264 (Main) ([27][0][0][0] / 0x001B), 
yuv420p(progressive), 1280x720, 60 fps, 60 tbr, 90k tbn, 180k tbc
    Stream #0:1[0x101]: Data: klv (KLVA / 0x41564C4B)
Output #0, data, to 'stream.txt':
  Metadata:
    encoder         : Lavf58.47.100
    Stream #0:0: Data: klv (KLVA / 0x41564C4B)
Stream mapping:
  Stream #0:1 -> #0:0 (copy)


  


  However, the contents of steram.txt are empty.
Please give me some advice.