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More completely flush WMA decoder state on seek to prevent artifact.

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Each MDCT depends on the previous frame for reconstruction.  Previosly these were not zeroed out when seeking, resulting in a few milliseconds of the previous frame playing with the current one.  Fix that.

Additionally, since the codec treats seeks to the start of a track as a "reset", flush the entire codec state in this event to ensure that everything is reset.

Change-Id: If593621a2922b0bbfa34f926f9bff31bee6b8c6a
This commit is contained in:
Michael Giacomelli 2012-04-03 20:15:16 -04:00
parent 905f920dc9
commit bc41926b8f
1 changed files with 13 additions and 7 deletions
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20
apps/codecs/wma.c Normal file → Executable file
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@ -54,14 +54,15 @@ enum codec_status codec_run(void)
int errcount = 0;
intptr_t param;
/* Proper reset of the decoder context. */
memset(&wmadec, 0, sizeof(wmadec));
/* Remember the resume position - when the codec is opened, the
playback engine will reset it. */
resume_offset = ci->id3->offset;
restart_track:
/* Proper reset of the decoder context. */
memset(&wmadec, 0, sizeof(wmadec));
if (codec_init()) {
LOGF("WMA: Error initialising codec\n");
return CODEC_ERROR;
@ -111,6 +112,15 @@ restart_track:
/* Deal with any pending seek requests */
if (action == CODEC_ACTION_SEEK_TIME) {
/*flush the wma decoder state*/
wmadec.last_superframe_len = 0;
wmadec.last_bitoffset = 0;
/*zero the frame out buffer so we don't overlap with a
stale samples*/
memset((*(wmadec.frame_out)), 0,
sizeof(fixed32) * MAX_CHANNELS * BLOCK_MAX_SIZE * 2);
if (param == 0) {
ci->set_elapsed(0);
ci->seek_complete();
@ -125,10 +135,6 @@ restart_track:
}
/*DEBUGF("Seek returned %d\n", (int)elapsedtime);*/
/*flush the wma decoder state*/
wmadec.last_superframe_len = 0;
wmadec.last_bitoffset = 0;
ci->set_elapsed(elapsedtime);
ci->seek_complete();
}