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• ffmpeg API h264 encoded video does not play on all platforms

  19 juillet 2012, par TheSHEEEP

  Edit : In the previous version I used a very old ffmpeg API. I now use the newest libraries. The problem has only changed slightly, from "Main" to "High".

  I am using the ffmpeg C API to create a mp4 video in C++.

  I want the resulting video to be of the profile "Constrained Baseline", so that the resulting video can be played on as much platforms as possible, especially mobile, but I get "High" profile every time, even though I hard coded the codec profile to be FF_PROFILE_H264_CONSTRAINED_BASELINE. As a result, the video does not play on all our testing platforms.

  This is what "ffprobe video.mp4 -show_streams" tells about my video streams :

    Metadata:
  
  major_brand     : isom
  
  minor_version   : 512
  
  compatible_brands: isomiso2avc1mp41
  
  creation_time   : 1970-01-01 00:00:00
  
  encoder         : Lavf53.5.0
  
    Duration: 00:00:13.20, start: 0.000000, bitrate: 553 kb/s
  
  Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 320x180,
  
  424 kb/s, 15 fps, 15 tbr, 15 tbn, 30 tbc
  
  Metadata:
  
    creation_time   : 1970-01-01 00:00:00
  
    handler_name    : VideoHandler
  
  Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, s16, 12
  
  kb/s
  
  Metadata:
  
    creation_time   : 1970-01-01 00:00:00
  
    handler_name    : SoundHandler
  
  -------VIDEO STREAM--------
  
  [STREAM] 
  
  index=0
  
  codec_name=h264
  
  codec_long_name=H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10
  
  
  
  profile=High <-- This should be "Constrained Baseline"
  
  
  
  codec_type=video
  
  codec_time_base=1/30
  
  codec_tag_string=avc1
  
  codec_tag=0x31637661
  
  width=320
  
  height=180
  
  has_b_frames=0
  
  sample_aspect_ratio=N/A
  
  display_aspect_ratio=N/A
  
  pix_fmt=yuv420p
  
  level=30
  
  timecode=N/A
  
  is_avc=1
  
  nal_length_size=4
  
  id=N/A
  
  r_frame_rate=15/1
  
  avg_frame_rate=15/1
  
  time_base=1/15
  
  start_time=0.000000
  
  duration=13.200000
  
  bit_rate=424252
  
  nb_frames=198
  
  nb_read_frames=N/A
  
  nb_read_packets=N/A
  
  TAG:creation_time=1970-01-01 00:00:00
  
  TAG:language=und
  
  TAG:handler_name=VideoHandler
  
  [/STREAM]
  
  -------AUDIO STREAM--------
  
  [STREAM]
  
  index=1
  
  codec_name=aac
  
  codec_long_name=Advanced Audio Coding
  
  profile=unknown
  
  codec_type=audio
  
  codec_time_base=1/44100
  
  codec_tag_string=mp4a
  
  codec_tag=0x6134706d
  
  sample_fmt=s16
  
  sample_rate=44100
  
  channels=2
  
  bits_per_sample=0
  
  id=N/A
  
  r_frame_rate=0/0
  
  avg_frame_rate=0/0
  
  time_base=1/44100
  
  start_time=0.000000
  
  duration=13.165714
  
  bit_rate=125301
  
  nb_frames=567
  
  nb_read_frames=N/A
  
  nb_read_packets=N/A
  
  TAG:creation_time=1970-01-01 00:00:00
  
  TAG:language=und
  
  TAG:handler_name=SoundHandler
  
  [/STREAM]

  This is the function I use to add a video stream. All the values that come from ptr-> are defined from outside, do those values have to be specific values to get the correct profile ? :

  static AVStream *add_video_stream( Cffmpeg_dll * ptr, AVFormatContext *oc, enum   CodecID codec_id )
  
  {
  
  AVCodecContext *c;
  
  AVStream *st;  
  
  AVCodec* codec;
  
  
  
  // Get correct codec
  
  codec = avcodec_find_encoder(codec_id);
  
  if (!codec) {
  
      av_log(NULL, AV_LOG_ERROR, "%s","Video codec not found\n");
  
      exit(1);
  
  }
  
  
  
  // Create stream
  
  st = avformat_new_stream(oc, codec);
  
  if (!st) {
  
      av_log(NULL, AV_LOG_ERROR, "%s","Could not alloc stream\n");
  
      exit(1);
  
  }
  
  
  
  c = st->codec;
  
  
  
  /* Get default values */
  
  codec = avcodec_find_encoder(codec_id);
  
  if (!codec) {
  
      av_log(NULL, AV_LOG_ERROR, "%s","Video codec not found (default values)\n");
  
      exit(1);
  
  }
  
  avcodec_get_context_defaults3(c, codec);
  
  
  
  c->codec_id = codec_id;
  
  c->codec_type = AVMEDIA_TYPE_VIDEO;
  
  
  
  c->bit_rate = ptr->video_bit_rate;
  
  av_log(NULL, AV_LOG_ERROR, " Bit rate: %i", c->bit_rate);
  
  
  
      c->qmin = ptr->qmin;
  
      c->qmax = ptr->qmax;
  
      c->me_method = ptr->me_method;
  
      c->me_subpel_quality = ptr->me_subpel_quality;
  
      c->i_quant_factor = ptr->i_quant_factor;
  
      c->qcompress = ptr->qcompress;
  
      c->max_qdiff = ptr->max_qdiff;
  
  
  
      // We need to set the level and profile to get videos that play (hopefully) on all platforms
  
      c->level = 30;
  
      c->profile = FF_PROFILE_H264_CONSTRAINED_BASELINE;
  
  
  
  c->width = ptr->dstWidth; 
  
  c->height = ptr->dstHeight; 
  
  
  
  c->time_base.den = ptr->fps;
  
  c->time_base.num = 1;
  
  c->gop_size = ptr->fps;
  
  c->pix_fmt = STREAM_PIX_FMT;
  
  c->max_b_frames = 0;
  
  
  
  // some formats want stream headers to be separate
  
  if(oc->oformat->flags & AVFMT_GLOBALHEADER)
  
      c->flags |= CODEC_FLAG_GLOBAL_HEADER;
  
  
  
  return st;
  
  }

  Additional info :

  As a reference video, I use the gizmo.mp4 that Mozilla serves as an example that plays on every platform/browser. It definitely has the "Constrained Baseline" profile, and definitely works on all our testing smartphones. You can download it here. Our self-created video doesn't work on all platforms and I'm convinced this is because of the profile.

  I am also using qt-faststart.exe to move the headers to the start of the file after creating the mp4, as this cannot be done in a good way in C++ directly. Could that be the problem ?

  Obviously, I am doing something wrong, but I don't know what it could be. I'd be thankful for every hint ;)

• ffmpeg converts .flv video to .gif with awful quality [migrated]

  22 février 2013, par Kamil Hismatullin

  I'm converting .flv movie to .gif file with ffmpeg.

  ffmpeg -i input.flv -ss 00:00:00.000 -pix_fmt rgb24 -r 10 -s 320x240 -t 00:00:10.000  output.gif

  It works great, but output gif file has a very law quality.

  Any ideas how can I improve quality of converted gif ?

  Output of command :

  $ ffmpeg -i input.flv -ss 00:00:00.000 -pix_fmt rgb24 -r 10 -s 320x240 -t 00:00:10.000  output.gif 
  
  
  
  ffmpeg version 0.8.5-6:0.8.5-0ubuntu0.12.10.1, Copyright (c) 2000-2012 the Libav developers
  
    built on Jan 24 2013 14:52:53 with gcc 4.7.2
  
  *** THIS PROGRAM IS DEPRECATED ***
  
  This program is only provided for compatibility and will be removed in a future release. Please use avconv instead.
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.flv':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 0
  
      compatible_brands: isommp42
  
      creation_time   : 2013-02-14 04:00:07
  
    Duration: 00:00:18.85, start: 0.000000, bitrate: 3098 kb/s
  
      Stream #0.0(und): Video: h264 (High), yuv420p, 1280x720, 2905 kb/s, 25 fps, 25 tbr, 50 tbn, 50 tbc
  
      Metadata:
  
        creation_time   : 1970-01-01 00:00:00
  
      Stream #0.1(und): Audio: aac, 44100 Hz, stereo, s16, 192 kb/s
  
      Metadata:
  
        creation_time   : 2013-02-14 04:00:07
  
  [buffer @ 0x92a8ea0] w:1280 h:720 pixfmt:yuv420p
  
  [scale @ 0x9215100] w:1280 h:720 fmt:yuv420p -> w:320 h:240 fmt:rgb24 flags:0x4
  
  Output #0, gif, to 'output.gif':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 0
  
      compatible_brands: isommp42
  
      creation_time   : 2013-02-14 04:00:07
  
      encoder         : Lavf53.21.1
  
      Stream #0.0(und): Video: rawvideo, rgb24, 320x240, q=2-31, 200 kb/s, 90k tbn, 10 tbc
  
      Metadata:
  
        creation_time   : 1970-01-01 00:00:00
  
  Stream mapping:
  
    Stream #0.0 -> #0.0
  
  Press ctrl-c to stop encoding
  
  frame=  101 fps= 32 q=0.0 Lsize=    8686kB time=10.10 bitrate=7045.0kbits/s dup=0 drop=149    
  
  video:22725kB audio:0kB global headers:0kB muxing overhead -61.778676%

  Thanks.

• ffmpeg - Incompatible sample format '(null)'

  17 juin 2012, par abrahab

  I convert videos from different sources with ffmpeg to mp4 with libx264 codec. After conversation time to time I got incorrect format error when trying to load already converted video with ffmpeg : Incompatible sample format '(null)' for codec 'aac', auto-selecting format 's16'

  Seems, it is audio stream problem with aac codec ? How to fix or how to convert videos to mp4 to be sure that I will not get the following error ? Maybe somehow need to specify audio format at the ffmpeg convert command ?

  ps. Video must work at Iphone/Ipad.
  pps. the main problem, that such videos with the following error can not be pseudo-streamed with nginx (got 500 Error)
  ppps. and sorry for my bad english, please, correct my text if need. thanks.

  Some additional info from file :

    Duration: 00:00:10.30, start: 0.000000, bitrate: 614 kb/s
  
      Stream #0.0(rus): Video: h264 (High), yuv420p, 1024x576, 567 kb/s, 23.98 fps, 23.98 tbr, 24k tbn, 47.95 tbc
  
      Metadata:
  
        creation_time   : 1970-01-01 00:00:00
  
      Stream #0.1(rus): Audio: aac, 22050 Hz, stereo, s16, 57 kb/s
  
      Metadata:
  
        creation_time   : 1970-01-01 00:00:00