On 15.02.2018 10:07, Raman Shishniou wrote:
On 02/15/2018 10:22 AM, Georg Chini wrote:
On 14.02.2018 23:09, Raman Shishniou wrote:
On 02/15/2018 12:03 AM, Georg Chini wrote:
The null-source currently reports the negative of the correct latency.
Also the memchunk passed to pa_source_post() is not initialized with
silence.
This patch fixes both issues.
---
src/modules/module-null-source.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/src/modules/module-null-source.c b/src/modules/module-null-source.c
index 41f17bd9..6310bda9 100644
--- a/src/modules/module-null-source.c
+++ b/src/modules/module-null-source.c
@@ -100,7 +100,7 @@ static int source_process_msg(pa_msgobject *o, int code,
void *data, int64_t off
pa_usec_t now;
now = pa_rtclock_now();
- *((int64_t*) data) = (int64_t)u->timestamp - (int64_t)now;
+ *((int64_t*) data) = (int64_t)now - (int64_t)u->timestamp;
return 0;
}
@@ -142,8 +142,9 @@ static void thread_func(void *userdata) {
if ((chunk.length = pa_usec_to_bytes(now - u->timestamp,
&u->source->sample_spec)) > 0) {
- chunk.memblock = pa_memblock_new(u->core->mempool, (size_t)
-1); /* or chunk.length? */
+ chunk.memblock = pa_memblock_new(u->core->mempool,
chunk.length);
chunk.index = 0;
+ pa_silence_memchunk(&chunk, &u->source->sample_spec);
pa_source_post(u->source, &chunk);
pa_memblock_unref(chunk.memblock);
I think you need to change the next line too:
- u->timestamp = now;
+ u->timestamp += pa_bytes_to_usec(chunk.length,
&u->source->sample_spec);
}
to make silence generator more stable
How would that make it more stable? It will only lower the precision of the
time stamp.
Nope. It will increase the precision. Actually null-source send
pa_bytes_to_usec(chunk.length)
microseconds of data each iteration which can be smaller than (now -
u->timestamp).
It must increase timestamp by actually data sent. Accumulated difference will
be corrected
on the next iteration by sending more data.
For example each 10ms we need to send a 99.5 bytes of data (s8, mono, 9950Hz),
i.e. pa_usec_to_bytes() does: bytes = usecs * 0.00995
and pa_bytes_to_usec() does: usecs = bytes / 0.00995
First iteration:
u->timestamp == 0
now = pa_rtclock_now() == 10ms == 10000us
bytes = pa_usec_to_bytes(10000 - 0) = 99
... send 99 bytes of data ...
u->timestamp += pa_bytes_to_usec(99) == 9949
Second iteration:
u->timestamp == 9949
now = pa_rtclock_now() == 20ms == 20000us
bytes = pa_usec_to_bytes(20000 - 9949) = 100
... send 100 bytes of data ...
u->timestamp += pa_bytes_to_used(100) = 9949 + 10050 = 19999
Third iteration:
u->timestamp == 19999
now = pa_rtclock_now() == 30ms == 30000us
bytes = pa_usec_to_bytes(30000 - 19999) = 99
... send 99 bytes of data ...
u->timestamp += pa_bytes_to_used(99) = 19999 + 9949 = 29948
and so on
Current implementation will send only 99 bytes of data each iteration.
--
Raman
Yes, you are right. I thought the timer was set to the real time consumed
by the number of samples generated and not to the specified latency.
I'll correct this, though probably by changing the timer value.
_______________________________________________
pulseaudio-discuss mailing list
pulseaudio-discuss@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss
