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Provide high resolution volume and prescaler to hosted targets.

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HAVE_SW_VOLUME_CONTROL is required and at this time only affects the
SDL targets using pcm-sdl.c.

Enables balance control in SDL targets, unless mono volume is in use.

Compiles software volume control as unbuffered when
PCM_SW_VOLUME_UNBUFFERED is defined. This avoids the overhead and
extra latency introduced by the double buffer when it is not needed.
Use this config when the target's PCM driver is buffered and sufficient
latency exists to perform safely the volume scaling.

Simulated targets that are double-buffered when made as native targets
remain so in the sim in order to run the same code.

Change-Id: Ifa77d2d3ae7376c65afecdfc785a084478cb5ffb
Reviewed-on: http://gerrit.rockbox.org/457
Reviewed-by: Michael Sevakis <jethead71@rockbox.org>
Tested-by: Michael Sevakis <jethead71@rockbox.org>
This commit is contained in:
Michael Sevakis 2013-04-23 03:20:49 -04:00
parent 370ed6de7c
commit 08199cd6cb
9 changed files with 189 additions and 106 deletions
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23
firmware/target/hosted/sdl/pcm-sdl.c
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@ -51,12 +51,6 @@
extern bool debug_audio;
#endif
#ifdef HAVE_SW_VOLUME_CONTROL
static int sim_volume = SDL_MIX_MAXVOLUME;
#else
static int sim_volume = 0;
#endif
#if CONFIG_CODEC == SWCODEC
static int cvt_status = -1;
@ -177,10 +171,10 @@ static void write_to_soundcard(struct pcm_udata *udata)
cvt.len = rd * pcm_sample_bytes;
cvt.buf = (Uint8 *) malloc(cvt.len * cvt.len_mult);
memcpy(cvt.buf, pcm_data, cvt.len);
pcm_copy_buffer(cvt.buf, pcm_data, cvt.len);
SDL_ConvertAudio(&cvt);
SDL_MixAudio(udata->stream, cvt.buf, cvt.len_cvt, sim_volume);
memcpy(udata->stream, cvt.buf, cvt.len_cvt);
udata->num_in = cvt.len / pcm_sample_bytes;
udata->num_out = cvt.len_cvt / pcm_sample_bytes;
@ -223,8 +217,8 @@ static void write_to_soundcard(struct pcm_udata *udata)
}
} else {
udata->num_in = udata->num_out = MIN(udata->num_in, udata->num_out);
SDL_MixAudio(udata->stream, pcm_data,
udata->num_out * pcm_sample_bytes, sim_volume);
pcm_copy_buffer(udata->stream, pcm_data,
udata->num_out * pcm_sample_bytes);
#ifdef DEBUG
if (udata->debug != NULL) {
fwrite(pcm_data, sizeof(Uint8), udata->num_out * pcm_sample_bytes,
@ -418,13 +412,4 @@ void pcm_play_dma_postinit(void)
{
}
#ifndef HAVE_SW_VOLUME_CONTROL
void pcm_set_mixer_volume(int volume)
{
int minvol = sound_min(SOUND_VOLUME);
int volrange = sound_max(SOUND_VOLUME) - minvol;
sim_volume = SDL_MIX_MAXVOLUME * (volume / 10 - minvol) / volrange;
}
#endif /* HAVE_SW_VOLUME_CONTROL */
#endif /* CONFIG_CODEC == SWCODEC */