actions/itgmania212121
1
0
Fork 0
Code Issues Pull Requests Actions 1 Packages Projects Releases Wiki Activity

minor Alsa9Buf::GetNumFramesToFill fix

Browse Source
This commit is contained in:
Glenn Maynard
2004-03-25 02:47:41 +00:00
parent 034800535e
commit 8d6c956ce1
1 changed files with 17 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files
stepmania/src/arch/Sound/ALSA9Helpers.cpp
+17 -7
View File
@@ -228,9 +228,9 @@ Alsa9Buf::~Alsa9Buf()
}
/* Don't fill the buffer any more than than "writeahead". Don't write any
* more than "chunksize" at a time. (These numbers are hints; if the hardware
* parameters require it, they can be ignored.) */
/* Don't fill the buffer any more than than "writeahead" frames. Prefer to
* write "chunksize" frames at a time. (These numbers are hints; if the
* hardware parameters require it, they can be ignored.) */
int Alsa9Buf::GetNumFramesToFill( snd_pcm_sframes_t writeahead, snd_pcm_sframes_t chunksize )
{
/* We have to write at least xfer_align bytes. */
@@ -240,7 +240,7 @@ int Alsa9Buf::GetNumFramesToFill( snd_pcm_sframes_t writeahead, snd_pcm_sframes_
* fill one chunk ahead, and underrun. */
writeahead = max( writeahead, chunksize*2 );
snd_pcm_sframes_t avail_frames = dsnd_pcm_avail_update(pcm);
snd_pcm_sframes_t avail_frames = dsnd_pcm_avail_update(pcm);
if( avail_frames > total_frames )
{
@@ -270,11 +270,21 @@ int Alsa9Buf::GetNumFramesToFill( snd_pcm_sframes_t writeahead, snd_pcm_sframes_
return 0;
}
/* Number of frames that have data: */
const snd_pcm_sframes_t filled_frames = max( 0l, total_frames - avail_frames );
snd_pcm_sframes_t frames_to_fill = clamp( writeahead - filled_frames, 0l, (snd_pcm_sframes_t)writeahead );
frames_to_fill = min( frames_to_fill, chunksize );
/* Number of frames that don't have data, that are within the writeahead: */
snd_pcm_sframes_t unfilled_frames = clamp( writeahead - filled_frames, 0l, (snd_pcm_sframes_t)writeahead );
/* If we have less than a chunk empty, don't fill at all. Otherwise, we'll
* spend a lot of CPU filling in partial chunks, instead of waiting for some
* sound to play and then filling a whole chunk at once. */
if( unfilled_frames < chunksize )
return 0;
/* We must always return a multiple of xfer_align. This might cause less than chunksize
* to be returned; that's OK. */
snd_pcm_sframes_t frames_to_fill = chunksize;
frames_to_fill -= frames_to_fill % xfer_align;
return frames_to_fill;