Re: MSACM: initialize some ACMSTREAMHEADER fields for the sake of native codecs

[Eric Pouech]

Alex Villací­s Lasso wrote:
> The ACMAPP sample application from MSDN reveals this annoying bug in 
> playback: with a native ACM codec (such as the Ogg Vorbis one bundled 
> with some Japanese RPGs), builtin msacm will successfully tell the codec 
> to decode the first two frames of compressed audio, and then the sound 
> will loop on these two frames. What is really happening is that winmm is 
> using double-buffering, and reusing the ACMSTREAMHEADER structures for 
> playback, and acmStreamConvert simply passes the structures into the 
> codec, without clearing cb[Src|Dst]LengthUsed (here is the bug) which 
> was set in the previous call to acmStreamConvert on that 
> ACMSTREAMHEADER. The native codec *expects* these fields to be set to 0, 
> and refuses to decode otherwise.
> well, you should check who is supposed to clear those flags between 
> msacm or winmm (I suppose wavemap).
> A+
> -- 
> Eric Pouech

MSACM: initialize some ACMSTREAMHEADER fields for the sake of native codecs

[Alex Villací­s Lasso]

Eric Pouech wrote:
> Alex Villací­s Lasso wrote:
> > The ACMAPP sample application from MSDN reveals this annoying bug in 
> > playback: with a native ACM codec (such as the Ogg Vorbis one bundled 
> > with some Japanese RPGs), builtin msacm will successfully tell the 
> > codec to decode the first two frames of compressed audio, and then 
> > the sound will loop on these two frames. What is really happening is 
> > that winmm is using double-buffering, and reusing the ACMSTREAMHEADER 
> > structures for playback, and acmStreamConvert simply passes the 
> > structures into the codec, without clearing cb[Src|Dst]LengthUsed 
> > (here is the bug) which was set in the previous call to 
> > acmStreamConvert on that ACMSTREAMHEADER. The native codec *expects* 
> > these fields to be set to 0, and refuses to decode otherwise.
>
> well, you should check who is supposed to clear those flags between 
> msacm or winmm (I suppose wavemap).
> A+

Native msacm (WINEDLLOVERRIDES=msacm32=n) works correctly (no loops) 
with native codecs in wine. This suggests that msacm is doing the 
clearing, since it is using the same builtin winmm.

Alex Villacís Lasso

MSACM: initialize some ACMSTREAMHEADER fields for the sake of native codecs

[Eric Pouech]

> Native msacm (WINEDLLOVERRIDES=msacm32=n) works correctly (no loops) 
> with native codecs in wine. This suggests that msacm is doing the 
> clearing, since it is using the same builtin winmm.
> fair enough

-- 
Eric Pouech