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authorMax Kellermann <max@duempel.org>2009-03-09 19:25:26 +0100
committerMax Kellermann <max@duempel.org>2009-03-09 19:25:26 +0100
commit3291666b570b1d20f59db42936eaa37dbeb9ca65 (patch)
treec3905d60131c9f440d8ca7d7d1ec45cecce02d85 /src/output_all.c
parentab3d7c29dae44f39df28c85e26b108c44fdbc4bf (diff)
downloadmpd-3291666b570b1d20f59db42936eaa37dbeb9ca65.tar.gz
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output: play from a music_pipe object
Instead of passing individual buffers to audio_output_all_play(), pass music_chunk objects. Append all those chunks asynchronously to a music_pipe instance. All output threads may then read chunks from this pipe. This reduces MPD's internal latency by an order of magnitude.
Diffstat (limited to 'src/output_all.c')
-rw-r--r--src/output_all.c224
1 files changed, 182 insertions, 42 deletions
diff --git a/src/output_all.c b/src/output_all.c
index 7b308a428..c1353fa71 100644
--- a/src/output_all.c
+++ b/src/output_all.c
@@ -20,6 +20,12 @@
#include "output_internal.h"
#include "output_control.h"
#include "conf.h"
+#include "pipe.h"
+#include "buffer.h"
+
+#ifndef NDEBUG
+#include "chunk.h"
+#endif
#include <assert.h>
#include <string.h>
@@ -32,6 +38,17 @@ static struct audio_format input_audio_format;
static struct audio_output *audio_outputs;
static unsigned int num_audio_outputs;
+/**
+ * The #music_buffer object where consumed chunks are returned.
+ */
+static struct music_buffer *g_music_buffer;
+
+/**
+ * The #music_pipe object which feeds all audio outputs. It is filled
+ * by audio_output_all_play().
+ */
+static struct music_pipe *g_mp;
+
unsigned int audio_output_count(void)
{
return num_audio_outputs;
@@ -179,60 +196,63 @@ audio_output_all_update(void)
for (i = 0; i < num_audio_outputs; ++i)
ret = audio_output_update(&audio_outputs[i],
- &input_audio_format) || ret;
+ &input_audio_format, g_mp) || ret;
return ret;
}
bool
-audio_output_all_play(const char *buffer, size_t length)
+audio_output_all_play(struct music_chunk *chunk)
{
- bool ret = false;
+ bool ret;
unsigned int i;
- assert(length > 0);
- /* no partial frames allowed */
- assert((length % audio_format_frame_size(&input_audio_format)) == 0);
+ assert(g_music_buffer != NULL);
+ assert(g_mp != NULL);
+ assert(chunk != NULL);
+ assert(music_chunk_check_format(chunk, &input_audio_format));
- audio_output_all_update();
+ ret = audio_output_all_update();
+ if (!ret)
+ return false;
+
+ music_pipe_push(g_mp, chunk);
for (i = 0; i < num_audio_outputs; ++i)
if (audio_output_is_open(&audio_outputs[i]))
- audio_output_play(&audio_outputs[i],
- buffer, length);
-
- while (true) {
- bool finished = true;
-
- for (i = 0; i < num_audio_outputs; ++i) {
- struct audio_output *ao = &audio_outputs[i];
-
- if (!audio_output_is_open(ao))
- continue;
-
- if (audio_output_command_is_finished(ao))
- ret = true;
- else {
- finished = false;
- audio_output_signal(ao);
- }
- }
-
- if (finished)
- break;
-
- notify_wait(&audio_output_client_notify);
- };
+ audio_output_play(&audio_outputs[i]);
return ret;
}
bool
-audio_output_all_open(const struct audio_format *audio_format)
+audio_output_all_open(const struct audio_format *audio_format,
+ struct music_buffer *buffer)
{
bool ret = false, enabled = false;
unsigned int i;
+ assert(buffer != NULL);
+ assert(g_music_buffer == NULL || g_music_buffer == buffer);
+ assert((g_mp == NULL) == (g_music_buffer == NULL));
+
+ g_music_buffer = buffer;
+
+ /* the audio format must be the same as existing chunks in the
+ pipe */
+ assert(audio_format == NULL || g_mp == NULL ||
+ music_pipe_check_format(g_mp, audio_format));
+
+ if (g_mp == NULL)
+ g_mp = music_pipe_new();
+ else
+ /* if the pipe hasn't been cleared, the the audio
+ format must not have changed */
+ assert(music_pipe_size(g_mp) == 0 ||
+ audio_format == NULL ||
+ audio_format_equals(audio_format,
+ &input_audio_format));
+
if (audio_format != NULL)
input_audio_format = *audio_format;
@@ -257,6 +277,121 @@ audio_output_all_open(const struct audio_format *audio_format)
return ret;
}
+/**
+ * Has the specified audio output already consumed this chunk?
+ */
+static bool
+chunk_is_consumed_in(const struct audio_output *ao,
+ const struct music_chunk *chunk)
+{
+ if (ao->chunk == NULL)
+ return false;
+
+ assert(chunk == ao->chunk || music_pipe_contains(g_mp, ao->chunk));
+
+ if (chunk != ao->chunk) {
+ assert(chunk->next != NULL);
+ return true;
+ }
+
+ return ao->chunk_finished && chunk->next == NULL;
+}
+
+/**
+ * Has this chunk been consumed by all audio outputs?
+ */
+static bool
+chunk_is_consumed(const struct music_chunk *chunk)
+{
+ for (unsigned i = 0; i < num_audio_outputs; ++i) {
+ const struct audio_output *ao = &audio_outputs[i];
+ bool consumed;
+
+ if (!ao->open)
+ continue;
+
+ g_mutex_lock(ao->mutex);
+ consumed = chunk_is_consumed_in(ao, chunk);
+ g_mutex_unlock(ao->mutex);
+
+ if (!consumed)
+ return false;
+ }
+
+ return true;
+}
+
+/**
+ * There's only one chunk left in the pipe (#g_mp), and all audio
+ * outputs have consumed it already. Clear the reference.
+ */
+static void
+clear_tail_chunk(const struct music_chunk *chunk, bool *locked)
+{
+ assert(chunk->next == NULL);
+ assert(music_pipe_contains(g_mp, chunk));
+
+ for (unsigned i = 0; i < num_audio_outputs; ++i) {
+ struct audio_output *ao = &audio_outputs[i];
+
+ locked[i] = ao->open;
+
+ if (!locked[i])
+ continue;
+
+ /* this mutex will be unlocked by the caller when it's
+ ready */
+ g_mutex_lock(ao->mutex);
+
+ assert(ao->chunk == chunk);
+ assert(ao->chunk_finished);
+ ao->chunk = NULL;
+ }
+}
+
+unsigned
+audio_output_all_check(void)
+{
+ const struct music_chunk *chunk;
+ bool is_tail;
+ struct music_chunk *shifted;
+ bool locked[num_audio_outputs];
+
+ assert(g_music_buffer != NULL);
+ assert(g_mp != NULL);
+
+ while ((chunk = music_pipe_peek(g_mp)) != NULL) {
+ assert(music_pipe_size(g_mp) > 0);
+
+ if (!chunk_is_consumed(chunk))
+ /* at least one output is not finished playing
+ this chunk */
+ return music_pipe_size(g_mp) - 1;
+
+ is_tail = chunk->next == NULL;
+ if (is_tail)
+ /* this is the tail of the pipe - clear the
+ chunk reference in all outputs */
+ clear_tail_chunk(chunk, locked);
+
+ /* remove the chunk from the pipe */
+ shifted = music_pipe_shift(g_mp);
+ assert(shifted == chunk);
+
+ if (is_tail)
+ /* unlock all audio outputs which were locked
+ by clear_tail_chunk() */
+ for (unsigned i = 0; i < num_audio_outputs; ++i)
+ if (locked[i])
+ g_mutex_unlock(audio_outputs[i].mutex);
+
+ /* return the chunk to the buffer */
+ music_buffer_return(g_music_buffer, shifted);
+ }
+
+ return 0;
+}
+
void
audio_output_all_pause(void)
{
@@ -278,12 +413,19 @@ audio_output_all_cancel(void)
audio_output_all_update();
+ /* send the cancel() command to all audio outputs */
+
for (i = 0; i < num_audio_outputs; ++i) {
if (audio_output_is_open(&audio_outputs[i]))
audio_output_cancel(&audio_outputs[i]);
}
audio_output_wait_all();
+
+ /* clear the music pipe and return all chunks to the buffer */
+
+ if (g_mp != NULL)
+ music_pipe_clear(g_mp, g_music_buffer);
}
void
@@ -293,16 +435,14 @@ audio_output_all_close(void)
for (i = 0; i < num_audio_outputs; ++i)
audio_output_close(&audio_outputs[i]);
-}
-void
-audio_output_all_tag(const struct tag *tag)
-{
- unsigned int i;
+ if (g_mp != NULL) {
+ assert(g_music_buffer != NULL);
- for (i = 0; i < num_audio_outputs; ++i)
- if (audio_output_is_open(&audio_outputs[i]))
- audio_output_send_tag(&audio_outputs[i], tag);
+ music_pipe_clear(g_mp, g_music_buffer);
+ music_pipe_free(g_mp);
+ g_mp = NULL;
+ }
- audio_output_wait_all();
+ g_music_buffer = NULL;
}