[Scummvm-devel] MPEG Changing Channel Count Midstream

[Matthew Hoops]

Hi again,

It seems that there was another problem causing it to report a
different channel count in the first place. LordHoto fixed the problem
in r52272, so it was really a looping problem. Sorry to have bothered
anyone (though, this e-mail never got replies in the first place, so I
doubt anyone was really bothered :P).

-Matt

On Thu, Aug 19, 2010 at 1:55 AM, Matthew Hoops <clone2727 at gmail.com> wrote:
> Hi,
>
> Last week, Julien (IRC: Littleboy) discovered that the DVD version of
> Riven would crash with this assertion: "Assertion failed:
> input.isStereo() == stereo, file sound/rate.cpp, line 286" for certain
> sounds. Digging deeper into the problem, it seems that MPEG-1 sounds
> (Layer II in this case) support doing changing the channel count
> throughout the stream and that triggers the assertion.
>
> Judging from the way the RateConverter is currently set up in ScummVM,
> it doesn't seem too easy to be able to allow for this behavior. I
> wrote up a quick and very hacky patch (which is attached) that
> switches MP3Stream to always return true for isStereo() and then when
> the current channel count is 1, just duplicate the sample for both
> left and right. Does anyone have a better idea on how to do this or a
> better suggestion of how to handle it?
>
> Thanks,
> Matt
>