[FFmpeg-devel] [RFC] be more kind with wrong psm in mpeg ps

Baptiste Coudurier baptiste.coudurier
Mon Apr 7 17:38:03 CEST 2008

M?ns Rullg?rd wrote:
> Baptiste Coudurier wrote:
>> M?ns Rullg?rd wrote:
>>> Baptiste Coudurier wrote:
>>>> Hi,
>>>> Attached patch make ps demuxer correctly detects lpcm files with wrong
>>>> psm (mplayer and vlc plays them correctly).
>>>> Should fix wrong_psm_lpcm.mpg on mplayerhq.
>>>> I think those checks are reasonable. Comments ?
>>> I don't like it.  It can break valid files.
>> Question is does it ?
>> I'd like some real measures of the effects of the psm considering vlc
>> and mplayer ignore it and play many files.
>> if psm says AC3 or DTS then fine, but if psm says private data or mpeg1
>> audio, it's reasonable to guess that it is not what psm says.
> Why?  I admit that I can't recall ever seeing such a file, but I wouldn't
> discount the possibility entirely.

Because until we encounter such files, we can still support files we have.
Besides, if psm says ac3 or dts, this patch won't break playback.

> IMO, people who create broken files don't deserve to have them played.

This is a position I can understand and to which I would agree too,
however, I also understand that FFmpeg goal is to play as many files as
we reasonably can. Those checks are reasonable IMHO.

> Rather than adding dubious support for broken files, create a tool
> to edit the PSM.

We can also ignore it like vlc and mplayer, those play more files that
libavformat atm.

>> I think I'll ask for a vote on this, since I would really like being
>> able to play those files.
> Didn't we agree that voting is bad?

Well, I think voting is good when 2 valid points are be to considered.

Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
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