[MPlayer-dev-eng] Re: Forgotten patches/bugreports/etc

Arpi arpi at thot.banki.hu
Tue Aug 19 23:03:59 CEST 2003


> So I'd have to assume then the information is bad as I've noticed this
> mostly with VCD format mpeg1 files that are cbr?
> I assume the values for video and audio bitrate that mplayer prints on
> startup are from the headers? I get this from a VCD:
> VIDEO:  MPEG1  352x240  (aspect 12)  29.97 fps  1150.0 kbps (143.8 kbyte/s)
> [V] filefmt:2  fourcc:0x10000001  size:352x240  fps:29.97  ftime:=0.0334
> MPEG 1.0, Layer II, 44100 Hz 224 kbit Stereo, BPF: 731
> Channels: 2, copyright: No, original: No, CRC: Yes, emphasis: 0
> AUDIO: 44100 Hz, 2 ch, 16 bit (0x10), ratio: 28000->176400 (224.0 kbit)
> For this file, file size is 448938328 bytes, length 2579.4 seconds
> (according to mplayer output). So the bitrates known by mplayer
> should lead to the almost correct length and seeking should work as
> 448938328/2579.4*8 is 1392.38 kbps.  Not exactly 1374 kbps, but close. But
> mplayer shows length as 52:03 instead and seeks accordingly.

yes, but the mpeg demuxer dont know about the audio bitrate(s), it only
uses the video bitrate. it was never intend to be accurte, as most of my
samples have wrong (usually too big) video bitrate.

it was enough for relative seeks (+-15s is acceptable insteda of +-10s)
and it will never work for absolute seeks.

when pnis enforced the remaining time display on osd, i said that it wont
work ok, but the conclusion was that it's still better than nothing.

anyway if you have a clean way of fixing this, send a patch...

calculating audio bitrates (note that -s, there may be multiple aud tracks)
into seeking is difficult or impossible in g1, due to design.
it is solved in g2, but it still may be wrong.
maybe parsing out stream rate from some PS or GOP headers could help.
unfortunatelly i have no docs on PS header details :(

A'rpi / Astral & ESP-team

Developer of MPlayer, the Movie Player for Linux - http://www.MPlayerHQ.hu
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