[pulseaudio-tickets] [PulseAudio] #837: A52 (ac3/Dolby Digital) encoding for SPDIF / Pulseaudio

[PulseAudio]

#837: A52 (ac3/Dolby Digital) encoding for SPDIF / Pulseaudio
----------------------+-----------------------------------------------------
  Reporter:  mcarans  |       Owner:  lennart      
      Type:  defect   |      Status:  closed       
 Milestone:  0.9.22   |   Component:  module-alsa-*
Resolution:  fixed    |    Keywords:               
----------------------+-----------------------------------------------------

Comment(by mcarans):

 New versions of Pulseaudio will be patched, but in the meantime, here are
 the revised steps for Ubuntu Lucid 10.04 LTS:

 {{{
 1. Open from Pulse source code: src/modules/alsa/alsa-sink.c

 2. Replace: pa_sink_set_max_rewind(u->sink, u->hwbuf_size); with:
 if (pa_alsa_pcm_is_hw(u->pcm_handle)) {
     pa_sink_set_max_rewind(u->sink, u->hwbuf_size);
 } else {
     pa_log("Disabling rewind for device %s", u->device_name);
     pa_sink_set_max_rewind(u->sink, 0);
 }

 3. Replace: pa_sink_set_max_rewind_within_thread(u->sink, u->hwbuf_size);
 with:
 if (pa_alsa_pcm_is_hw(u->pcm_handle)) {
     pa_sink_set_max_rewind_within_thread(u->sink, u->hwbuf_size);
 } else {
     pa_log("Disabling rewind_within_thread for device %s",
 u->device_name);
     pa_sink_set_max_rewind_within_thread(u->sink, 0);
 }

 4. After line: if (PA_UNLIKELY((sframes =
 snd_pcm_mmap_commit(u->pcm_handle, offset, frames)) < 0)) { add:
 if (!after_avail && (int) sframes == -EAGAIN)
     break;

 5. Compile and install Pulseaudio with udev support

 6. Copy /etc/pulse/daemon.conf to ~/.pulse/daemon.conf and ensure it has
 uncommented: default-sample-rate = 48000

 7. Edit ~/.asoundrc and put in it:
 pcm.a52 {
    @args [CARD]
    @args.CARD {
        type string
    }
    type rate
    slave {
        pcm {
            type a52
            bitrate 448
            channels 6
            card $CARD
        }
        rate 48000 #required somehow, otherwise nothing happens in
 PulseAudio
    }

 8. sudo alsa reload

 9. Make sure you do not have a ~/.pulse/default.pa or if you do, that it
 is using load-module module-udev-detect to load Alsa sinks not load-module
 module-alsa-sink ...

 10. pulseaudio -k and pulseaudio -D
 }}}

-- 
Ticket URL: <http://pulseaudio.org/ticket/837#comment:16>
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