[MPlayer-dev-eng] [PATCH] Fix demux_avi >=2GB overflow & enhance avi info output

[eviv bulgroz]

Hi,
Thanks for your help and advices, I'll try that and maybe shift this whole dwLength tangling to
read_avi_header too. I've one question though. As asked, I won't remvove the original i_bps
calulation code and use it as a fallback when no index is available. But I can't figure out what  

  if(sh_audio) sh_video->i_bps-=sh_audio->audio.dwLength;

is doing? shouldn't it be rather something like:

  if(sh_audio && sh_audio->wf->nAvgBytesPerSec) 
    sh_video->i_bps-= (float)sh_audio->wf->nAvgBytesPerSec*
    sh_audio->audio.dwLength*sh_audio->audio.dwScale/sh_audio->audio.dwRate;


--- Arpi <arpi at thot.banki.hu> wrote:
> Hi,
> 
> ok, the problem is right (and known, by me) but your fix is buggy too:
> 
> > -  // calculating video bitrate:
> > -  sh_video->i_bps=demuxer->movi_end-demuxer->movi_start-priv->idx_size*8;
> > -  if(sh_audio) sh_video->i_bps-=sh_audio->audio.dwLength;
> > -  mp_msg(MSGT_DEMUX,MSGL_V,"AVI video length=%lu\n",(unsigned long)sh_video->i_bps);
> > -  sh_video->i_bps=((float)sh_video->i_bps/(float)sh_video->video.dwLength)*sh_video->fps;
> > -  
> > -  if((priv->numberofframes=sh_video->video.dwLength)<=1)
> > -    // bad video header, try to get number of frames from audio
> > -    if(sh_audio && sh_audio->wf->nAvgBytesPerSec)
> priv->numberofframes=sh_video->fps*sh_audio->audio.dwLength/sh_audio->wf->nAvgBytesPerSec;
> 
> this code shouldn't be removed, but used as fallback if no index (maybe with
> a warning saying that values are inaccurate, and/or printing '~' sign before
> teh numbers)
> 
> > +  // calc video bitrate, count idx, calc a/v size & fix dwLength if needed:
> 
> > +    sh_video->video.dwLength=0;
> > +    sh_audio->audio.dwLength=0;
> > +    for(i=0;i<priv->idx_size;i++){ 
> > +      if(sh_video->ds->id == avi_stream_id(((AVIINDEXENTRY *)priv->idx)[i].ckid)) {
> > +        vsize+=((AVIINDEXENTRY *)priv->idx)[i].dwChunkLength;
> > +        sh_video->video.dwLength++;
> > +      }
> > +      else if(sh_audio->ds->id == avi_stream_id(((AVIINDEXENTRY *)priv->idx)[i].ckid)) {
> > +        asize+=((AVIINDEXENTRY *)priv->idx)[i].dwChunkLength;
> > +        sh_audio->audio.dwLength++;
> > +      }
> 
> this is BAD.
> dwLength is counted in samples, not in chunks.
> also, calculating the right sample number is very tricky for audio, esp. for
> VBR. you need to round up chunksize to N * nBlockAlign, so:
> 
> dwLength += (dwChunkLength+nBlockAlign-1)/nBlockAlign;
> 
> but also check that nBlockAlign is valid, and fallback to dwSampleSize if
> that valid and fallback to nBitsPerSample/8*mChannels and so on...
> see demux_avi.c, for the "right" way of calculating number of samples...
> 
> 
> A'rpi / Astral & ESP-team
> 
> --
> Developer of MPlayer, the Movie Player for Linux - http://www.MPlayerHQ.hu
> _______________________________________________
> MPlayer-dev-eng mailing list
> MPlayer-dev-eng at mplayerhq.hu
> http://mplayerhq.hu/mailman/listinfo/mplayer-dev-eng


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