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• Full HD video converted to FLV, slow playback in browser

  12 février 2012, par Boyan Georgiev

  I rendered a full HD video using Adobe AfterEffects CS5 in mp4 format. It plays just fine. I've got this video app to which I fed the mp4 file. The video app converts the mp4 to flv format and makes the video available via a web page. I've downloaded the resulting flv file to my local PC - it plays just fine in my VLC player. But, the problem is I'm getting awful playback inside my browser.

  I've made sure the issue is not bandwidth related.
  Both original mp4 file, and ffmpeg-converted FLV file, play perfectly using VLC player.
  I've tested the FLV file with two players - Agryia FLV Player Elite and JW Player. Both players play the video awfully - really slow and very choppy.

  Here's my ffmpeg -i myflvfile.flv :
  `

  Seems stream 0 codec frame rate differs from container frame rate: 119.88 (120000/1001) -> 59.92 (719/12)
  
  Input #0, flv, from '94044631305552037.flv':
  
  Metadata:
  
  duration        : 146
  
  width           : 1920
  
  height          : 1080
  
  videodatarate   : 684
  
  framerate       : 60
  
  videocodecid    : 7
  
  audiodatarate   : 62
  
  audiosamplerate : 22050
  
  audiosamplesize : 16
  
  stereo          : true
  
  audiocodecid    : 2
  
  major_brand     : mp42
  
  minor_version   : 0
  
  compatible_brands: mp42mp41
  
  creation_time   : 2012-02-10 00:55:19
  
  encoder         : Lavf52.111.0
  
  filesize        : 61969316
  
  Duration: 00:02:25.77, start: 0.034000, bitrate: 764 kb/s
  
  Stream #0.0: Video: h264 (High), yuv420p, 1920x1080 [PAR 3:4 DAR 4:3], 700 kb/s, 59.92 tbr, 1k tbn, 119.88 tbc
  
  Stream #0.1: Audio: mp3, 22050 Hz, stereo, s16, 64 kb/s`

  Can any one point me in the right direction here ? Why is playback perfect with VLC player of both the mp4 and the flv file on my local PC, yet in my browser, using two different players, the playback is so bad ?

  PS Here's my convert command :

  ffmpeg -y -i /var/www/sandverlag.com/htdocs/rmtk/videos/originals/94044631305552038.mp4 -vcodec libx264 -ar 22050 -ac 2 -vb 700000 -s 1920x1080 -crf 22 -threads 0 -f flv /var/www/sandverlag.com/htdocs/rmtk/videos/converted/94044631305552038.flv > /dev/null &    

• AVCodecContext settings for H264 (1080i)

  23 septembre 2013, par moose

  I'm trying to configure x264 for 1080i capturing. Most of these settings below are found in different examples. However, compiled together they don't work. ffmpeg API reports no error, but avcodec_encode_video() always returns zero.

  Some of the numbers are strange to me... for example, gop_size. Isn't 250 too high ?

  Event you can't offer the final answer, I'm still interested in any kind of comment on this subject.

  pCodecContext->codec_type              = AVMEDIA_TYPE_VIDEO;
  
  pCodecContext->codec_id                = CODEC_ID_H264;
  
  
  
  pCodecContext->coder_type              = FF_CODER_TYPE_AC;
  
  pCodecContext->flags                  |= CODEC_FLAG_LOOP_FILTER | CODEC_FLAG_INTERLACED_ME | CODEC_FLAG_INTERLACED_DCT;
  
  pCodecContext->me_cmp                 |= 1;
  
  pCodecContext->partitions             |= X264_PART_I8X8 | X264_PART_I4X4 | X264_PART_P8X8 | X264_PART_B8X8;
  
  pCodecContext->me_method               = ME_UMH;
  
  pCodecContext->me_subpel_quality       = 8;
  
  pCodecContext->me_range                = 16;
  
  
  
  pCodecContext->bit_rate                = 10 * 1024 * 1024; // 10 Mbps??
  
  pCodecContext->width                   = 1920;
  
  pCodecContext->height                  = 1080;
  
  
  
  pCodecContext->time_base.num           = 1;    // 25 fps
  
  pCodecContext->time_base.den           = 25;   // 25 fps
  
  
  
  pCodecContext->gop_size                = 250; // 250
  
  pCodecContext->keyint_min              = 25;
  
  pCodecContext->scenechange_threshold   = 40;
  
  pCodecContext->i_quant_factor          = 0.71f;
  
  pCodecContext->b_frame_strategy        = 1;
  
  pCodecContext->qcompress               = 0.6f;
  
  pCodecContext->qmin                    = 10;
  
  pCodecContext->qmax                    = 51;
  
  pCodecContext->max_qdiff               = 4;
  
  pCodecContext->max_b_frames            = 3;
  
  pCodecContext->refs                    = 4;
  
  pCodecContext->directpred              = 3;
  
  pCodecContext->trellis                 = 1;
  
  pCodecContext->flags2                 |= CODEC_FLAG2_WPRED | CODEC_FLAG2_MIXED_REFS | CODEC_FLAG2_8X8DCT | CODEC_FLAG2_FASTPSKIP;  // wpred+mixed_refs+dct8x8+fastpskip
  
  pCodecContext->weighted_p_pred         = 2; // not implemented with interlaced ??
  
  pCodecContext->crf                     = 22;
  
  
  
  pCodecContext->pix_fmt                 = PIX_FMT_YUV420P;
  
  
  
  pCodecContext->thread_count            = 0;

• Access to folders on Ubuntu-based Rails server (keep getting "No such file..")

  13 avril 2012, par Stpn

  I am setting up Rails+ffmpeg on Ubuntu and I keep getting

   Errno::ENOENT
  
   No such file or directory..

  The setup is as follows :

  /home/username/RailsApp
  /home/username/videos/

  I am trying to run ffmpeg to write to /home/username/videos and I used "/home/username/videos/" and " /videos/" but no luck..

  What am I missing ?

  "www-data" user is included in "username" group..

  Rails app works fine otherwise..

  Any input greatly appreciated !

  Thanks !