[pulseaudio-discuss] [PATCH] null-source: correct latency report and silence memory

[Georg Chini]

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.