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• libaomenc : enable 8, 10 and 12 bit RGB encoding

  16 juillet 2020, par Lynne

  libaomenc : enable 8, 10 and 12 bit RGB encoding
  RGB pixel formats are one occasion where by pixel format we mean
  
  pixel format, primaries, transfer characteristic, and matrix coeffs,
  
  so we have to manually set them as they're set to unspecified by
  
  default, despite there only being a single possible combination.
  

  • [DH] libavcodec/libaomenc.c

• 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 how to use https dynamic url as input for amovie filter

  2 juillet 2020, par Johny Sharma

  Basically what i am trying to do is to calling a dynamic php url which is generating a audio file for me and just want to use that file as an input for amovie filter.
I hope you have understand my question.

  


  What i have done so far ?

  


  I have a FFMPEG code which is :

  


  ffmpeg-y -i 'bg-file.mp3' -c copy -map 0:0 -map 1:0 -filter_complex "amovie='/auth.php?input=string&l=hi&f.mp3':loop=999[sc][mix];[0:a][sc]sidechaincompress=threshold=0.100:ratio=20,volume=10dB:precision=fixed[bg], [bg][mix]amix=duration=first"  -c:a libmp3lame -ac 2  "save.mp3"


  


  This line is calling my dynamic url for generating the required song.

  


  "amovie='/auth.php?input=string&l=hi&f.mp3'


  


  Everything is working if i check them apart. but when i use them together the ffmpeg is giving the following error.

  


  [22] => [Parsed_amovie_0 @ 0x1378140] Failed to avformat_open_input '/auth.php?input=string&l=hi&f.mp3':loop=999'
[23] => [AVFilterGraph @ 0x1368ca0] Error initializing filter 'amovie' with args '/auth.php?input=string&l=hi&f.mp3':loop=999'
[24] => Error initializing complex filters.
[25] => No such file or directory


  


  I dont know is it possible to put a dynamically generated url as an input for amovie filter or not ?
if i open my dynamic url in browser its works like a mp3 file and play similar to any mp3 file.

  


  using this code to play that mp3 :

  


  header('Content-Description: File Transfer');
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename='.basename($path));
header('Content-Transfer-Encoding: binary');
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Pragma: public');
ob_clean();
flush();
readfile($path);
exit;


  


  This one looks similar to my query but slightly different and that's why i am still looking for a solution

  


  How to use https input with ffmpeg "amovie" filter ?