From 39107956ab680b37ade979e5379cf98a06604b13 Mon Sep 17 00:00:00 2001 From: Michael Sevakis Date: Fri, 7 Jan 2011 05:17:28 +0000 Subject: MPEGPlyaer: A bit of audio mutation. Remove a useless thread state. Take some control over the buffer away from the audio thread itself. Some atomicity corrections. git-svn-id: svn://svn.rockbox.org/rockbox/trunk@28984 a1c6a512-1295-4272-9138-f99709370657 --- apps/plugins/mpegplayer/pcm_output.c | 150 ++++++++++++++++++++++++++--------- 1 file changed, 111 insertions(+), 39 deletions(-) (limited to 'apps/plugins/mpegplayer/pcm_output.c') diff --git a/apps/plugins/mpegplayer/pcm_output.c b/apps/plugins/mpegplayer/pcm_output.c index a5d8f86e5b..0b8ad7701a 100644 --- a/apps/plugins/mpegplayer/pcm_output.c +++ b/apps/plugins/mpegplayer/pcm_output.c @@ -36,21 +36,30 @@ static struct pcm_frame_header * ALIGNED_ATTR(4) pcmbuf_tail IBSS_ATTR; /* Bytes */ static ssize_t pcmbuf_curr_size IBSS_ATTR; /* Size of currently playing frame */ -static uint64_t pcmbuf_read IBSS_ATTR; /* Number of bytes read by DMA */ -static uint64_t pcmbuf_written IBSS_ATTR; /* Number of bytes written by source */ +static ssize_t pcmbuf_read IBSS_ATTR; /* Number of bytes read by DMA */ +static ssize_t pcmbuf_written IBSS_ATTR; /* Number of bytes written by source */ static ssize_t pcmbuf_threshold IBSS_ATTR; /* Non-silence threshold */ /* Clock */ -static uint32_t clock_base IBSS_ATTR; /* Our base clock */ static uint32_t clock_start IBSS_ATTR; /* Clock at playback start */ -static int32_t clock_adjust IBSS_ATTR; /* Clock drift adjustment */ +static uint32_t volatile clock_tick IBSS_ATTR; /* Our base clock */ +static uint32_t volatile clock_time IBSS_ATTR; /* Timestamp adjusted */ -int pcm_skipped = 0; -int pcm_underruns = 0; +static int pcm_skipped = 0; +static int pcm_underruns = 0; /* Small silence clip. ~5.80ms @ 44.1kHz */ static int16_t silence[256*2] ALIGNED_ATTR(4) = { 0 }; +/* Delete all buffer contents */ +static void pcm_reset_buffer(void) +{ + pcmbuf_threshold = PCMOUT_PLAY_WM; + pcmbuf_curr_size = pcmbuf_read = pcmbuf_written = 0; + pcmbuf_head = pcmbuf_tail = pcm_buffer; + pcm_skipped = pcm_underruns = 0; +} + /* Advance a PCM buffer pointer by size bytes circularly */ static inline void pcm_advance_buffer(struct pcm_frame_header **p, size_t size) @@ -60,15 +69,16 @@ static inline void pcm_advance_buffer(struct pcm_frame_header **p, *p = SKIPBYTES(*p, -PCMOUT_BUFSIZE); } -/* Inline internally but not externally */ -inline ssize_t pcm_output_used(void) +/* Return physical space used */ +static inline ssize_t pcm_output_bytes_used(void) { - return (ssize_t)(pcmbuf_written - pcmbuf_read); + return pcmbuf_written - pcmbuf_read; /* wrap-safe */ } -inline ssize_t pcm_output_free(void) +/* Return physical space free */ +static inline ssize_t pcm_output_bytes_free(void) { - return (ssize_t)(PCMOUT_BUFSIZE - pcmbuf_written + pcmbuf_read); + return PCMOUT_BUFSIZE - pcm_output_bytes_used(); } /* Audio DMA handler */ @@ -80,7 +90,7 @@ static void get_more(unsigned char **start, size_t *size) pcmbuf_read += pcmbuf_curr_size; pcmbuf_curr_size = 0; - sz = pcm_output_used(); + sz = pcm_output_bytes_used(); if (sz > pcmbuf_threshold) { @@ -89,16 +99,15 @@ static void get_more(unsigned char **start, size_t *size) while (1) { uint32_t time = pcmbuf_head->time; - int32_t offset = time - (clock_base + clock_adjust); + int32_t offset = time - clock_time; sz = pcmbuf_head->size; - if (sz < (ssize_t)(sizeof(pcmbuf_head) + 4) || + if (sz < (ssize_t)(PCM_HDR_SIZE + 4) || (sz & 3) != 0) { /* Just show a warning about this - will never happen - * without a bug in the audio thread code or a clobbered - * buffer */ + * without a corrupted buffer */ DEBUGF("get_more: invalid size (%ld)\n", (long)sz); } @@ -108,11 +117,12 @@ static void get_more(unsigned char **start, size_t *size) pcm_advance_buffer(&pcmbuf_head, sz); pcmbuf_read += sz; pcm_skipped++; - if (pcmbuf_read < pcmbuf_written) + if (pcm_output_bytes_used() > 0) continue; /* Ran out so revert to default watermark */ pcmbuf_threshold = PCMOUT_PLAY_WM; + pcm_underruns++; } else if (offset < 100*CLOCK_RATE/1000) { @@ -122,15 +132,15 @@ static void get_more(unsigned char **start, size_t *size) pcm_advance_buffer(&pcmbuf_head, sz); pcmbuf_curr_size = sz; - sz -= sizeof (struct pcm_frame_header); + sz -= PCM_HDR_SIZE; *size = sz; /* Audio is time master - keep clock synchronized */ - clock_adjust = time - clock_base; + clock_time = time + (sz >> 2); /* Update base clock */ - clock_base += sz >> 2; + clock_tick += sz >> 2; return; } /* Frame will be dropped - play silence clip */ @@ -150,22 +160,57 @@ static void get_more(unsigned char **start, size_t *size) *start = (unsigned char *)silence; *size = sizeof (silence); - clock_base += sizeof (silence) / 4; + clock_tick += sizeof (silence) / 4; + clock_time += sizeof (silence) / 4; - if (pcmbuf_read > pcmbuf_written) + if (sz < 0) pcmbuf_read = pcmbuf_written; } -struct pcm_frame_header * pcm_output_get_buffer(void) +/** Public interface **/ + +/* Return a buffer pointer if at least size bytes are available and if so, + * give the actual free space */ +unsigned char * pcm_output_get_buffer(ssize_t *size) { - return pcmbuf_tail; + ssize_t sz = *size; + ssize_t free = pcm_output_bytes_free() - PCM_HDR_SIZE; + + if (sz >= 0 && free >= sz) + { + *size = free; /* return actual free space (- header) */ + return pcmbuf_tail->data; + } + + /* Leave *size alone so caller doesn't have to reinit */ + return NULL; } -void pcm_output_add_data(void) +/* Commit the buffer returned by pcm_ouput_get_buffer; timestamp is PCM + * clock time units, not video format time units */ +bool pcm_output_commit_data(ssize_t size, uint32_t timestamp) { - size_t size = pcmbuf_tail->size; + if (size <= 0 || (size & 3)) + return false; /* invalid */ + + size += PCM_HDR_SIZE; + + if (size > pcm_output_bytes_free()) + return false; /* too big */ + + pcmbuf_tail->size = size; + pcmbuf_tail->time = timestamp; + pcm_advance_buffer(&pcmbuf_tail, size); pcmbuf_written += size; + + return true; +} + +/* Returns 'true' if the buffer is completely empty */ +bool pcm_output_empty(void) +{ + return pcm_output_bytes_used() <= 0; } /* Flushes the buffer - clock keeps counting */ @@ -182,10 +227,7 @@ void pcm_output_flush(void) if (playing) rb->pcm_play_stop(); - pcmbuf_threshold = PCMOUT_PLAY_WM; - pcmbuf_curr_size = pcmbuf_read = pcmbuf_written = 0; - pcmbuf_head = pcmbuf_tail = pcm_buffer; - pcm_skipped = pcm_underruns = 0; + pcm_reset_buffer(); /* Restart if playing state was current */ if (playing && !paused) @@ -201,25 +243,54 @@ void pcm_output_set_clock(uint32_t time) { rb->pcm_play_lock(); - clock_base = time; clock_start = time; - clock_adjust = 0; + clock_tick = time; + clock_time = time; rb->pcm_play_unlock(); } +/* Return the clock as synchronized by audio frame timestamps */ uint32_t pcm_output_get_clock(void) { - return clock_base + clock_adjust - - (rb->pcm_get_bytes_waiting() >> 2); + uint32_t time, rem; + + /* Reread if data race detected - rem will be 0 if driver hasn't yet + * updated to the new buffer size. Also be sure pcm state doesn't + * cause indefinite loop. + * + * FYI: NOT scrutinized for rd/wr reordering on different cores. */ + do + { + time = clock_time; + rem = rb->pcm_get_bytes_waiting() >> 2; + } + while (UNLIKELY(time != clock_time || + (rem == 0 && rb->pcm_is_playing() && !rb->pcm_is_paused()))); + + return time - rem; + } +/* Return the raw clock as counted from the last pcm_output_set_clock + * call */ uint32_t pcm_output_get_ticks(uint32_t *start) { + uint32_t tick, rem; + + /* Same procedure as pcm_output_get_clock */ + do + { + tick = clock_tick; + rem = rb->pcm_get_bytes_waiting() >> 2; + } + while (UNLIKELY(tick != clock_tick || + (rem == 0 && rb->pcm_is_playing() && !rb->pcm_is_paused()))); + if (start) *start = clock_start; - return clock_base - (rb->pcm_get_bytes_waiting() >> 2); + return tick - rem; } /* Pauses/Starts pcm playback - and the clock */ @@ -267,12 +338,13 @@ bool pcm_output_init(void) if (pcm_buffer == NULL) return false; - pcmbuf_threshold = PCMOUT_PLAY_WM; - pcmbuf_head = pcm_buffer; - pcmbuf_tail = pcm_buffer; pcmbuf_end = SKIPBYTES(pcm_buffer, PCMOUT_BUFSIZE); - pcmbuf_curr_size = pcmbuf_read = pcmbuf_written = 0; + pcm_reset_buffer(); + + /* Some targets could play at the movie frequency without resampling but + * as of now DSP assumes a certain frequency (always 44100Hz) so + * resampling will be needed for other movie audio rates. */ rb->pcm_set_frequency(NATIVE_FREQUENCY); #if INPUT_SRC_CAPS != 0 -- cgit v1.2.3