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• FFmpeg add #EXT-X-START to HLS m3u8 file

  25 octobre 2017, par bosboy

  I am creating a HLS live streaming event playlist (m3u8 file and the ts segments) via FFmpeg. The segments at the beginning must not be removed from the playlist (it should contain all the segments). The HTML5 video element should start playing the video at the very beginning (by default it starts somewhere in the middle if the playlist contains several segments and the end tag is not contained at the end of the playlist file). To achieve that the video starts playing at the very beginning I need to add #EXT-X-START:TIME-OFFSET=0 to the playlist file.

  Currently my FFmpeg command is the following :
  ffmpeg -i videoSrc -map 0 -f hls -hls_time 10 -hls_list_size 0 -hls_playlist_type event -hls_allow_cache 0 -hls_segment_filename testSegmented%03d.ts testSegmentedHls.m3u8.

  So my question is : How do I add #EXT-X-START:TIME-OFFSET=0 to my HLS m3u8 playlist file using FFmpeg ?

• FFMPEG bat file won't run [closed]

  8 octobre 2023, par Tiecubed

  @echo off
setlocal enableextensions enabledelayedexpansion

set "input_directory=C:\Users\tiecu\OneDrive\Desktop\testing environment\Pending"
set "output_directory=C:\Users\tiecu\OneDrive\Desktop\testing environment\Output"

for %%i in ("%input_directory%.mp4") do (
    set "input_file=%%i"
    set "output_file=!output_directory!%%~nxi"

    C:\ffmpeg\ffmpeg.exe -i "!input_file!" -map_metadata -1 -vf "rotate=2PI/180, vignette=1.1, scale=1200:-1,setsar=1,crop=1080:1920,setpts=PTS/1.1" -af "atempo=1.1" -c:v libx264 -crf 18 -c:a aac -strict experimental "!output_file!"
)


  


  I have tried many bat scripts, all of them work except ffmpeg ones. The terminal opens and immediately closes. I have tried many scripts. ffmpeg works fine via cmd without a batch script. I'm entirely lost. It was working fine earlier, then in the middle of making the script it stopped working. So I went back to the previous working script and it would no longer work. Terminal opens and immediately closes.

  


• QTFF, ISO 14496-12 and elst-media_time value

  5 mars 2021, par aymv
  

  1. What is the priority standard for decoding mov files ?

  


  2. What value should be set in elst/media_time ? Can we check it somehow ?

  


  


  

  • In QuickTime File Format Specification media_time is DT value :

  


  


  


  The edit list atom provides the initial DT value if it is nonempty
(nonzero).

  


  


  

  • In ISO IEC 14496-12 media_time is CT value.

  


  


  


  The Edit List Box provides the initial CT value if it is non‐empty
(non‐zero).

  


  


  It looks like the media_time value can be calculated and checked with CT + ctts (for ISO IEC 14496-12). But how to interpret the next note ?

  


  


  Edits are not restricted to fall on sample times. This means that when
entering an edit, it can be necessary to (a) back up to a sync point,
and pre‐roll from there and then (b) be careful about the duration of
the first sample — it might have been truncated if the edit enters it
during its normal duration. If this is audio, that frame might need to
be decoded, and then the final slicing done. Likewise, the duration of
the last sample in an edit might need slicing.

  


  


  Does this mean that the media_time may not indicate a specific PTS of the first frame but in the "middle" of two frames for example ? But I did not find in the standard how to work with this situation and which of these two frames must be displayed in such a situation as the first frame.