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• avformat/smacker : Improve timestamps

  24 juin 2020, par Andreas Rheinhardt

  avformat/smacker : Improve timestamps
  A Smacker file can contain up to seven audio tracks. Up until now,
  
  the pts for the i. audio packet contained in a Smacker frame was
  
  simply the end timestamp of the last i. audio packet contained in
  
  an earlier Smacker frame.
  The problem with this is that a Smacker stream need not contain data in
  
  every Smacker frame and so the current i. audio packet present may come
  
  from a different underlying stream than the last i. audio packet
  
  contained in an earlier frame.
  The sample hypnotix.smk* exhibits this. It has three audio tracks and
  
  the first of the three has a longer first packet, so that the audio for
  
  the first track is contained in only 235 packets contained in the first
  
  235 Smacker frames ; the end timestamp of this track is 166696 (about 7.56s
  
  at a timebase of 1/22050) ; the other two audio tracks both have 253 packets
  
  contained in the first 253 Smacker frames. Up until now, the 236th
  
  packet of the second track being the first audio packet in the 236th
  
  Smacker frame would get the end timestamp of the last first audio packet
  
  from the last Smacker frame containing a first audio packet and said
  
  last audio packet is the first audio packet from the 235th Smacker frame
  
  from the first audio track, so that the timestamp is 166696. In contrast,
  
  the 236th packet from the third track (whose packets contain the same number
  
  of samples as the packets from the second track) has a timestamp of
  
  156116 (because its timestamp is derived from the end timestamp of the
  
  235th packet of the second audio track). In the end, the second track
  
  ended up being 177360/22050 s = 8.044s long ; in contrast, the third
  
  track was 166780/22050 s = 7.56s long which also coincided with the
  
  video.
  This commit fixes this by not using timestamps from other tracks for
  
  a packet's pts.
  * : https://samples.ffmpeg.org/game-formats/smacker/wetlands/hypnotix.smk
  Reviewed-by : Timotej Lazar <timotej.lazar@araneo.si>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavformat/smacker.c

• Audio effect ( a 20ms delay between right and the left channel) using Web Audio API or any Javascript Audio Library like howler.js, tone.js ?

  15 juillet 2020, par questionare_101

  I was wondering if there any option in howler.js, tone.js or any other javascript audio library which I can use to add a 20ms delay between the right and the left channel which makes the audio listening experience more immersive.

  


  Can it be achieved using Audio sprites with howler.js ? (but I guess it can't separate the right and the left channels)
https://medium.com/game-development-stuff/how-to-create-audiosprites-to-use-with-howler-js-beed5d006ac1

  


  Is there any ?

  


  Have also asked the same quest here : https://github.com/goldfire/howler.js/issues/1374

  


  I usually enable this option under ffdshow audio processor while playing audio using MPC-HC (Mega Version) on my pc. I was wondering how can I do it using Web Audio API or howler.js ?

  


  

  


  Somewhat like this kind of effect : Just delay the either channel by 20ms
Like we do in Adobe Audition


  


• ffmpeg 'av_seek_frame()' not work in bink video

  19 juillet 2020, par ghoflvhxj

  I'm trying to play video in my game by using ffmpeg-avformatlib library.

  


  'av_seek_frame()' work correctly when open '.avi' file.

  


  but if open .bik file, it's not work however the function return 0(success) and seek to 0 frame.

  


  anyone who know about this problem ? :( please tell me please...

  


  void CMovie::Play(const Time startFrame, const Time endFrame, const bool loop/* = false*/)
{
    ...
    if (m_bStart)
    {
        av_seek_frame(GetFormatContext(), GetVideoStreamIndex(), startFrame, AVSEEK_FLAG_FRAME);
        m_bStart = false;
    }
    ...
}


  


  i uploaded sample video player and video which call 'av_seek_frame()' to seek.

  


  play fire.bik and click left or right button, you can see seek to 0 frame. it's same as my program.

  


  check it please.
https://drive.google.com/file/d/1DVrX3EOzjxSfEA4EYpeSREaE2RLhB28Q/view?usp=sharing