[Kdenlive-devel] [Mlt-devel] current mlt jack issues

[Dan Dennedy]

On Mon, Jun 25, 2012 at 12:37 AM, Ed Rogalsky
<ed.rogalsky at googlemail.com> wrote:
> Hi Dan,
>
>> I just integrated jack into Shotcut, which also uses OpenGL very
>> similarly, and I did not reproduce this problem.
>
> Ok. In this case I will investigate. Thanks anyways.
>
>
>
>> static int jack_process (jack_nframes_t frames, void * data)
>> {
>> ...
>> for ( i = 0; i < channels; i++ )
>> {
>> size_t jack_size = ( frames * sizeof(float) );
>> size_t ring_size;
>> // Send audio through out port
>> jack_output_buffers[i] = jack_port_get_buffer( jack_output_ports[i], frames
>> );
>> if ( ! jack_output_buffers[i] )
>> {
>> mlt_log_error( MLT_FILTER_SERVICE(filter), "no buffer for output port %d\n",
>> i );
>> err = 1;
>> break;
>> }
>> ring_size = jack_ringbuffer_read_space( output_buffers[i] );  <--- ring_size
>> = 0, nothing is copied to jackd
>> jack_ringbuffer_read( output_buffers[i], ( char * )jack_output_buffers[i],
>> ring_size < jack_size ? ring_size : jack_size );
>> ....
>> }
>>
>> the ring_size is 0 and no data is transfered to the jack outport
>
>>> This is the problem - jack playing unset memory. This is what I have
>>> committed and works for me using melt -jack -consumer sdl_preview.
>
> I had implemented in my private jack branch a similiar solution
> (silence buffer) for playing around. Ok I've integrated the patch - it
> works for me too.
> Thank you.
>
> Now I'm ready for the next step. I have some another issues in sync
> and seeking if audio tracks are muted or not available (using mlt jack
> only  as transport).

Are you attaching the jackrack filter to the consumer?

> But for describing the problem/issue I want to play a little bit more.
> I'll let you know if I have the details.
>
>
> regards
> eddrog