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• Move VLC and RL_VLC_ELEM structure definitions to a separate header

  14 mai 2016, par Alexandra Hájková

  Move VLC and RL_VLC_ELEM structure definitions to a separate header
  Use the newly created vlc.h directly instead of including get_bits when needed.
  
  The VLC and RL_VLC_ELEM structures are independent from the bitreader.
  Signed-off-by : Luca Barbato <lu_zero@gentoo.org>
  

  • [DBH] libavcodec/bitstream.c
  • [DBH] libavcodec/get_bits.h
  • [DBH] libavcodec/huffman.c
  • [DBH] libavcodec/huffman.h
  • [DBH] libavcodec/rl.c
  • [DBH] libavcodec/rl.h
  • [DBH] libavcodec/vlc.h

• Why DASH video fragments are not reproducible nor readable with ffmpeg ?

  21 mai 2020, par salgarji

  I'm streaming live video using DASH through FFmpeg. Everything's OK, fragments are generated, and the mpd file, but I wanted to have reproducible independent fragments. Video players won't open those fragments. I guess it's because they are mpd file dependant. My question would be : can those fragments be generated in a way that they are reproducible ? I don't know if it has something to do to the frames I P B or just the way dash cuts video information, in a way that it only saves 'timeline' on the mpd...

  



  My purpose is not only being able to reproduce them sepparately, but I need to insert information in a metadata tag of the video, and ffmpeg won't let me read those live streaming generated fragments.

  



  FFmpeg input information command will behave like this :

  



  input :

  



  ffmpeg -i /path/video0-0-1.mp4


  



  output :

  



  ffmpeg version N-97777-g3b5a36c56d Copyright (c) 2000-2020 the FFmpeg developers
  built with Apple clang version 11.0.3 (clang-1103.0.32.59)
  configuration: --enable-gpl --enable-libx264
  libavutil      56. 45.100 / 56. 45.100
  libavcodec     58. 84.100 / 58. 84.100
  libavformat    58. 43.100 / 58. 43.100
  libavdevice    58.  9.103 / 58.  9.103
  libavfilter     7. 81.100 /  7. 81.100
  libswscale      5.  6.101 /  5.  6.101
  libswresample   3.  6.100 /  3.  6.100
  libpostproc    55.  6.100 / 55.  6.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fb324009400] could not find corresponding track id 1
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fb324009400] could not find corresponding trex (id 1)
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fb324009400] could not find corresponding track id 0
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fb324009400] trun track id unknown, no tfhd was found
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fb324009400] error reading header
/path/video0-0-1.mp4: Invalid data found when processing input


  



  I execute this FFmpeg code using fluent-ffmpeg over JS to generate the fragments :

  



  var ffmpeg = require('fluent-ffmpeg');

var grabacion = new ffmpeg();

grabacion.addInput('0')
.inputOptions(['-y -nostdin', '-f avfoundation', '-video_size 1280x720', '-pix_fmt nv12', '-framerate 30'])
.outputOptions(['-vcodec libx264', '-keyint_min 0', '-g 100', '-map 0:v', '-b:v 1000k', '-f dash',
 '-use_template 1', '-use_timeline 0', '-init_seg_name video0-$RepresentationID$-$Number$.mp4',
 '-media_seg_name video0-$RepresentationID$-$Number$.mp4', '-remove_at_exit 0', '-window_size 20', '-seg_duration 4'])
.output('/path/path/path/video.mpd')
.run();


  



  So, the final purpose would be to be able to insert a tag like this :

  



  ffmpeg -i video0-0-0.mp4 -movflags use_metadata_tags -metadata sample_tag=whateveryouwanttoadd video0-0-0-tagged.mp4


  



  Is there any way to do it ? Thank you in advance !

  


• How to merge segmented webvtt subtitle files and output a single file ?

  15 février, par Dobbelina

  How to merge a segmented webvtt subtitle file and output a single file ?,
m3u8 looks like this example :

  



  #EXTM3U
#EXT-X-VERSION:4
#EXT-X-PLAYLIST-TYPE:VOD
#EXT-X-MEDIA-SEQUENCE:1
#EXT-X-INDEPENDENT-SEGMENTS
#EXT-X-TARGETDURATION:4
#USP-X-TIMESTAMP-MAP:MPEGTS=900000,LOCAL=1970-01-01T00:00:00Z
#EXTINF:4, no desc
0ghzi1b2cz5(11792107_ISMUSP)-textstream_swe=2000-1.webvtt
#EXTINF:4, no desc
0ghzi1b2cz5(11792107_ISMUSP)-textstream_swe=2000-2.webvtt
#EXTINF:4, no desc
0ghzi1b2cz5(11792107_ISMUSP)-textstream_swe=2000-3.webvtt
#EXTINF:4, no desc
0ghzi1b2cz5(11792107_ISMUSP)-textstream_swe=2000-4.webvtt
#EXTINF:4, no desc
0ghzi1b2cz5(11792107_ISMUSP)-textstream_swe=2000-5.webvtt
#EXTINF:4, no desc
0ghzi1b2cz5(11792107_ISMUSP)-textstream_swe=2000-6.webvtt
#EXT-X-ENDLIST


  



  I noticed that each segment is not synchronized/cued against total playing time, but against the individual ts segments.
If ffmpeg could be used to do this, what magic input do i need to give it ?

  



  A single correctly cued vtt or srt file is what i want.

  



  I have a great appetite and don't like chunks, lol !

  



  Thanks for any replies you lovely people !

  



  ---

  



  With this i get a merged vtt file, but the cues are all wrong :

  



  ffmpeg -i "https://cmoreseusphlsvod60.akamaized.net/vod/bea44/0ghzi1b2cz5(11792107_ISMUSP).ism/0ghzi1b2cz5(11792107_ISMUSP)-textstream_swe=2000.m3u8" -f segment -segment_time 4 -segment_format webvtt -scodec copy out-%05d.vtt


  



  Each segment is not synchronized/cued against total playing time, but against the individual ts segments.
Example output of above command :

  



  WEBVTT

00:00.000 --> 00:03.040
Du har aktier i ett företag
som saknar framtid.

00:00.000 --> 00:03.280
De vill ha aktierna.
Du känner dem inte, Olga.

00:00.000 --> 00:01.720
De som får Kastrups aktier vinner.


  



  Cues all start like this which isn't very helpfull : 00:00.000

  



  Some segments contains no cues, like segment 15 for example :
https://cmoreseusphlsvod60.akamaized.net/vod/bea44/0ghzi1b2cz5(11792107_ISMUSP).ism/0ghzi1b2cz5(11792107_ISMUSP)-textstream_swe=2000-15.webvtt

  



  


  "A WebVTT Segment MAY contain no cues ; this indicates that no
 subtitles are to be displayed during that period."