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authorJeffrey Goode <jeffg7@gmail.com>2009-11-11 07:02:18 +0000
committerJeffrey Goode <jeffg7@gmail.com>2009-11-11 07:02:18 +0000
commit0db3308cb56a1589b427f3b712d66480bc4d788f (patch)
tree85818b2e08662bc156ff5857834e3611f79e9911 /apps/pcmbuf.c
parentdb4cab0e665143a3eaa56bdd911a25f534db6caf (diff)
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pcmbuf: bug fix with pcmbuf flush, code cleanup, added comments
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@23608 a1c6a512-1295-4272-9138-f99709370657
Diffstat (limited to 'apps/pcmbuf.c')
-rw-r--r--apps/pcmbuf.c110
1 files changed, 56 insertions, 54 deletions
diff --git a/apps/pcmbuf.c b/apps/pcmbuf.c
index 580dc315a7..e62fc892cc 100644
--- a/apps/pcmbuf.c
+++ b/apps/pcmbuf.c
@@ -119,7 +119,7 @@ static struct chunkdesc *mix_chunk IDATA_ATTR;
static size_t pcmbuf_mix_sample IDATA_ATTR;
static bool low_latency_mode = false;
-static bool flush_pcmbuf;
+static bool flush_pcmbuf = false;
#ifdef HAVE_PRIORITY_SCHEDULING
static int codec_thread_priority = PRIORITY_PLAYBACK;
@@ -129,14 +129,14 @@ extern unsigned int codec_thread_id;
/* Helpful macros for use in conditionals this assumes some of the above
* static variable names */
-#define NEED_FLUSH(position) \
- (pcmbuffer_fillpos > PCMBUF_TARGET_CHUNK || position >= pcmbuf_size)
+#define COMMIT_IF_NEEDED if(pcmbuffer_fillpos > PCMBUF_TARGET_CHUNK || \
+ (pcmbuffer_pos + pcmbuffer_fillpos) >= pcmbuf_size) commit_chunk(false)
#define LOW_DATA(quarter_secs) \
(pcmbuf_unplayed_bytes < NATIVE_FREQUENCY * quarter_secs)
#ifdef HAVE_CROSSFADE
static void crossfade_start(void);
-static void flush_crossfade(char *buf, size_t length);
+static void write_to_crossfade(char *buf, size_t length);
static void pcmbuf_finish_crossfade_enable(void);
#endif
@@ -181,12 +181,10 @@ static bool show_desc(char *caller)
#endif
-/* Commit PCM data */
+/** Accept new PCM data */
-/**
- * Commit samples waiting to the pcm buffer.
- */
-static void commit_chunk(void)
+/* Commit PCM buffer samples as a new chunk for playback */
+static void commit_chunk(bool flush_next_time)
{
if (!pcmbuffer_fillpos)
return;
@@ -219,7 +217,7 @@ static void commit_chunk(void)
{
if (flush_pcmbuf)
{
- /* flush! discard all data after the currently playing chunk,
+ /* Flush! Discard all data after the currently playing chunk,
and make the current chunk play next */
write_end_chunk->link = read_chunk->link;
read_chunk->link = pcmbuf_current;
@@ -228,7 +226,6 @@ static void commit_chunk(void)
write_end_chunk = write_end_chunk->link;
pcmbuf_unplayed_bytes -= write_end_chunk->size;
}
- flush_pcmbuf = false;
}
/* If there is already a read buffer setup, add to it */
else
@@ -240,6 +237,11 @@ static void commit_chunk(void)
read_chunk = pcmbuf_current;
}
+ /* If flush_next_time is true, then the current chunk will be thrown out
+ * and the next chunk to be committed will be the next to be played.
+ * This is used to empty the PCM buffer for a track change. */
+ flush_pcmbuf = flush_next_time;
+
/* This is now the last buffer to read */
read_end_chunk = pcmbuf_current;
@@ -254,6 +256,7 @@ static void commit_chunk(void)
DISPLAY_DESC("commit_chunk");
}
+/* Set priority of the codec thread */
#ifdef HAVE_PRIORITY_SCHEDULING
static void boost_codec_thread(bool boost)
{
@@ -282,6 +285,8 @@ static void boost_codec_thread(bool boost)
#define boost_codec_thread(boost) do{}while(0)
#endif /* HAVE_PRIORITY_SCHEDULING */
+/* Return true if the PCM buffer is able to receive new data.
+ * Also maintain buffer level above the watermark. */
static bool prepare_insert(size_t length)
{
if (low_latency_mode)
@@ -295,7 +300,7 @@ static bool prepare_insert(size_t length)
if (pcmbuf_free() < length + PCMBUF_MIN_CHUNK)
return false;
- /* boost CPU if needed to either fill to watermark or for pre-buffer */
+ /* Maintain the buffer level above the watermark */
if (pcm_is_playing())
{
/* Only codec thread initiates boost - voice boosts the cpu when playing
@@ -328,9 +333,10 @@ static bool prepare_insert(size_t length)
}
else /* pcm_is_playing */
{
+ /* Boost CPU for pre-buffer */
trigger_cpu_boost();
- /* Pre-buffer up to watermark */
+ /* If pre-buffered to the watermark, start playback */
#if MEMORYSIZE > 2
if (!LOW_DATA(4))
#else
@@ -346,18 +352,23 @@ static bool prepare_insert(size_t length)
return true;
}
+/* Request space in the buffer for writing output samples */
void *pcmbuf_request_buffer(int *count)
{
#ifdef HAVE_CROSSFADE
+ /* we're going to crossfade to a new track, which is now on its way */
if (crossfade_track_change_started)
crossfade_start();
- if (crossfade_active) {
+ /* crossfade has begun, put the new track samples in fadebuf */
+ if (crossfade_active)
+ {
*count = MIN(*count, PCMBUF_MIX_CHUNK/4);
return fadebuf;
}
else
#endif
+ /* if possible, reserve room in the PCM buffer for new samples */
{
if(prepare_insert(*count << 2))
{
@@ -369,38 +380,34 @@ void *pcmbuf_request_buffer(int *count)
}
else
{
- /* Flush and wrap the buffer */
- commit_chunk();
+ /* Wrap the buffer, the new samples go at the beginning */
+ commit_chunk(false);
pcmbuffer_pos = 0;
return &pcmbuffer[0];
}
}
}
+ /* PCM buffer not ready to receive new data yet */
return NULL;
}
+/* Handle new samples to the buffer */
void pcmbuf_write_complete(int count)
{
size_t length = (size_t)(unsigned int)count << 2;
#ifdef HAVE_CROSSFADE
if (crossfade_active)
- {
- flush_crossfade(fadebuf, length);
- if (!(crossfade_fade_in_rem || crossfade_chunk))
- crossfade_active = false;
- }
+ write_to_crossfade(fadebuf, length);
else
#endif
{
pcmbuffer_fillpos += length;
-
- if (NEED_FLUSH(pcmbuffer_pos + pcmbuffer_fillpos))
- commit_chunk();
+ COMMIT_IF_NEEDED;
}
}
-/* Init */
+/** Init */
static inline void init_pcmbuffers(void)
{
@@ -466,14 +473,13 @@ size_t pcmbuf_init(unsigned char *bufend)
}
-/* Track change */
+/** Track change */
void pcmbuf_start_track_change(bool auto_skip)
{
bool crossfade = false;
#ifdef HAVE_CROSSFADE
/* Determine whether this track change needs to crossfade */
-
if(crossfade_enabled && !pcmbuf_is_crossfade_active())
{
switch(global_settings.crossfade)
@@ -524,8 +530,7 @@ void pcmbuf_start_track_change(bool auto_skip)
/* Not enough data, or not crossfading, flush the old data instead */
if (LOW_DATA(2) || !crossfade || low_latency_mode)
{
- flush_pcmbuf = true;
- commit_chunk();
+ commit_chunk(true);
return;
}
@@ -536,7 +541,7 @@ void pcmbuf_start_track_change(bool auto_skip)
crossfade_track_change_started = crossfade;
#endif
}
- else /* automatic and not crossfading, so gapless track change */
+ else /* automatic and not crossfading, so do gapless track change */
{
/* The codec is moving on to the next track, but the current track will
* continue to play. Set a flag to make sure the elapsed time of the
@@ -549,9 +554,9 @@ void pcmbuf_start_track_change(bool auto_skip)
}
-/* Playback */
+/** Playback */
-/** PCM driver callback
+/* PCM driver callback
* This function has 3 major logical parts (separated by brackets both for
* readability and variable scoping). The first part performs the
* operations related to finishing off the last chunk we fed to the DMA.
@@ -598,7 +603,7 @@ static void pcmbuf_pcm_callback(unsigned char** start, size_t* size)
if (pcmbuffer_fillpos && !read_chunk)
{
logf("pcmbuf_pcm_callback: commit last samples");
- commit_chunk();
+ commit_chunk(false);
}
}
@@ -625,7 +630,7 @@ static void pcmbuf_pcm_callback(unsigned char** start, size_t* size)
DISPLAY_DESC("callback");
}
-/* Force playback. */
+/* Force playback */
void pcmbuf_play_start(void)
{
if (!pcm_is_playing() && pcmbuf_unplayed_bytes && read_chunk != NULL)
@@ -658,7 +663,6 @@ void pcmbuf_play_stop(void)
#endif
end_of_track = false;
track_transition = false;
- flush_pcmbuf = false;
DISPLAY_DESC("play_stop");
/* Can unboost the codec thread here no matter who's calling */
@@ -675,7 +679,7 @@ void pcmbuf_pause(bool pause)
}
-/* Crossfade */
+/** Crossfade */
/* Clip sample to signed 16 bit range */
static inline int32_t clip_sample_16(int32_t sample)
@@ -686,9 +690,7 @@ static inline int32_t clip_sample_16(int32_t sample)
}
#ifdef HAVE_CROSSFADE
-/**
- * Completely process the crossfade fade out effect with current pcm buffer.
- */
+/* Completely process the crossfade fade-out effect with current PCM buffer */
static void crossfade_process_buffer(size_t fade_in_delay,
size_t fade_out_delay, size_t fade_out_rem)
{
@@ -747,8 +749,8 @@ static void crossfade_process_buffer(size_t fade_in_delay,
logf("process done!");
}
-/* Initializes crossfader, calculates all necessary parameters and
- * performs fade-out with the pcm buffer. */
+/* Initializes crossfader, calculates all necessary parameters and performs
+ * fade-out with the PCM buffer. */
static void crossfade_start(void)
{
size_t crossfade_rem;
@@ -766,7 +768,7 @@ static void crossfade_start(void)
}
logf("crossfade_start");
- commit_chunk();
+ commit_chunk(false);
crossfade_active = true;
/* Initialize the crossfade buffer size to all of the buffered data that
@@ -854,7 +856,8 @@ static size_t crossfade_mix(int factor, const char *buf, size_t length)
return 0;
}
-static void flush_crossfade(char *buf, size_t length)
+/* Perform fade-in of new track */
+static void write_to_crossfade(char *buf, size_t length)
{
if (length)
{
@@ -904,17 +907,13 @@ static void flush_crossfade(char *buf, size_t length)
return;
}
- /* Flush samples to the buffer */
+ /* Commit samples to the buffer */
while (!prepare_insert(length))
sleep(1);
while (length > 0)
{
+ COMMIT_IF_NEEDED;
size_t pcmbuffer_index = pcmbuffer_pos + pcmbuffer_fillpos;
- if (NEED_FLUSH(pcmbuffer_index))
- {
- commit_chunk();
- pcmbuffer_index = pcmbuffer_pos + pcmbuffer_fillpos;
- }
size_t copy_n = MIN(length, pcmbuf_size - pcmbuffer_index);
memcpy(&pcmbuffer[pcmbuffer_index], buf, copy_n);
buf += copy_n;
@@ -922,6 +921,9 @@ static void flush_crossfade(char *buf, size_t length)
length -= copy_n;
}
}
+ /* if no more fading-in to do, stop the crossfade */
+ if (!(crossfade_fade_in_rem || crossfade_chunk))
+ crossfade_active = false;
}
static void pcmbuf_finish_crossfade_enable(void)
@@ -962,7 +964,7 @@ bool pcmbuf_is_same_size(void)
#endif /* HAVE_CROSSFADE */
-/* Voice */
+/** Voice */
/* Returns pcm buffer usage in percents (0 to 100). */
static int pcmbuf_usage(void)
@@ -1058,7 +1060,7 @@ void pcmbuf_write_voice_complete(int count)
}
-/* Debug menu, other metrics */
+/** Debug menu, other metrics */
/* Amount of bytes left in the buffer. */
size_t pcmbuf_free(void)
@@ -1072,7 +1074,7 @@ size_t pcmbuf_free(void)
else
return (size_t) (read - write);
}
- return pcmbuf_size;
+ return pcmbuf_size - pcmbuffer_fillpos;
}
size_t pcmbuf_get_bufsize(void)
@@ -1097,7 +1099,7 @@ int pcmbuf_descs(void)
}
#ifdef ROCKBOX_HAS_LOGF
-unsigned char * pcmbuf_get_meminfo(size_t *length)
+unsigned char *pcmbuf_get_meminfo(size_t *length)
{
*length = pcmbuf_bufend - pcmbuffer;
return pcmbuffer;
@@ -1105,7 +1107,7 @@ unsigned char * pcmbuf_get_meminfo(size_t *length)
#endif
-/* Misc */
+/** Misc */
bool pcmbuf_is_lowdata(void)
{