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crossfade works much better but costs some cpu power if enabled.

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@6768 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Miika Pekkarinen 2005-06-19 20:20:16 +00:00
parent b08e2acf45
commit fe8eb3b698
1 changed files with 30 additions and 14 deletions
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40
firmware/pcm_playback.c
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@ -47,7 +47,8 @@
/* Must be a power of 2 */ /* Must be a power of 2 */
#define NUM_PCM_BUFFERS (PCMBUF_SIZE / CHUNK_SIZE) #define NUM_PCM_BUFFERS (PCMBUF_SIZE / CHUNK_SIZE)
#define NUM_PCM_BUFFERS_MASK (NUM_PCM_BUFFERS - 1) #define NUM_PCM_BUFFERS_MASK (NUM_PCM_BUFFERS - 1)
#define PCM_WATERMARK (CHUNK_SIZE * 6) #define PCM_WATERMARK (CHUNK_SIZE * 4)
#define PCM_CF_WATERMARK (PCMBUF_SIZE - CHUNK_SIZE*4)
static bool pcm_playing; static bool pcm_playing;
static bool pcm_paused; static bool pcm_paused;
@ -345,6 +346,7 @@ void pcm_watermark_callback(int bytes_left)
/* Fill audio buffer by boosting cpu */ /* Fill audio buffer by boosting cpu */
pcm_boost(true); pcm_boost(true);
if (bytes_left <= CHUNK_SIZE * 2)
crossfade_active = false; crossfade_active = false;
} }
@ -378,7 +380,7 @@ bool pcm_is_lowdata(void)
if (!pcm_is_playing() || pcm_paused) if (!pcm_is_playing() || pcm_paused)
return false; return false;
if (pcmbuf_unplayed_bytes < PCM_WATERMARK) if (pcmbuf_unplayed_bytes < PCM_WATERMARK || crossfade_active)
return true; return true;
return false; return false;
@ -386,14 +388,22 @@ bool pcm_is_lowdata(void)
bool pcm_crossfade_start(void) bool pcm_crossfade_start(void)
{ {
if (PCMBUF_SIZE - audiobuffer_free < CHUNK_SIZE * 4 || !crossfade_enabled) { if (PCMBUF_SIZE - audiobuffer_free < CHUNK_SIZE * 8 || !crossfade_enabled) {
return false; return false;
} }
logf("crossfading!"); logf("crossfading!");
if (audiobuffer_fillpos) {
while (!pcm_play_add_chunk(&audiobuffer[audiobuffer_pos],
audiobuffer_fillpos, pcm_event_handler)) {
yield();
}
pcm_event_handler = NULL;
}
pcm_boost(true); pcm_boost(true);
crossfade_active = true; crossfade_active = true;
crossfade_pos = audiobuffer_pos; crossfade_pos = audiobuffer_pos;
crossfade_amount = (PCMBUF_SIZE - audiobuffer_free - (CHUNK_SIZE * 4))/2; crossfade_amount = (PCMBUF_SIZE - audiobuffer_free - (CHUNK_SIZE * 6))/2;
crossfade_rem = crossfade_amount; crossfade_rem = crossfade_amount;
audiobuffer_fillpos = 0; audiobuffer_fillpos = 0;
@ -404,20 +414,22 @@ bool pcm_crossfade_start(void)
} }
static __inline static __inline
void crossfade(short *buf, const short *buf2, int length) int crossfade(short *buf, const short *buf2, int length)
{ {
int i, size; int i, size;
int val1 = (crossfade_rem)*1000/crossfade_amount;
int val2 = (crossfade_amount-crossfade_rem)*1000/crossfade_amount;
logf("cfi: %d/%d", length, crossfade_rem); logf("cfi: %d/%d", length, crossfade_rem);
size = MIN(length, crossfade_rem); size = MIN(length, crossfade_rem);
for (i = 0; i < length; i++) { for (i = 0; i < length; i++) {
/* This is not yet realtime, needs optimizations for crossfade to work. */ buf[i] = ((buf[i] * val1) + (buf2[i] * val2)) / 1000;
buf[i] = ((buf[i] * ((crossfade_rem)*1000/crossfade_amount))/1000)
+ ((buf2[i] * ((crossfade_amount-crossfade_rem)*1000/crossfade_amount))/1000);
} }
crossfade_rem -= i;
if (--crossfade_rem <= 0) if (crossfade_rem <= 0)
crossfade_active = false; crossfade_active = false;
return size;
} }
bool audiobuffer_insert(char *buf, size_t length) bool audiobuffer_insert(char *buf, size_t length)
@ -440,7 +452,7 @@ bool audiobuffer_insert(char *buf, size_t length)
if (crossfade_active) { if (crossfade_active) {
copy_n = MIN(length, PCMBUF_SIZE - (unsigned int)crossfade_pos); copy_n = MIN(length, PCMBUF_SIZE - (unsigned int)crossfade_pos);
crossfade((short *)&audiobuffer[crossfade_pos], copy_n = 2 * crossfade((short *)&audiobuffer[crossfade_pos],
(const short *)buf, copy_n/2); (const short *)buf, copy_n/2);
buf += copy_n; buf += copy_n;
length -= copy_n; length -= copy_n;
@ -497,10 +509,14 @@ void pcm_play_init(void)
pcmbuf_read_index = 0; pcmbuf_read_index = 0;
pcmbuf_write_index = 0; pcmbuf_write_index = 0;
pcmbuf_unplayed_bytes = 0; pcmbuf_unplayed_bytes = 0;
crossfade_enabled = false; crossfade_active = false;
pcm_event_handler = NULL; pcm_event_handler = NULL;
if (crossfade_enabled) {
pcm_play_set_watermark(PCM_CF_WATERMARK, pcm_watermark_callback);
} else {
pcm_play_set_watermark(PCM_WATERMARK, pcm_watermark_callback); pcm_play_set_watermark(PCM_WATERMARK, pcm_watermark_callback);
} }
}
void pcm_crossfade_enable(bool on_off) void pcm_crossfade_enable(bool on_off)
{ {