[alsa-devel] Status of Dolby Digital on-the-fly encoding? (via a52 plugin)
I am trying to output Dolby Digital data via coaxial cable to the Logitech Z-5450 5.1 speaker set. Presumably, a52 is the right plugin for this, taking six channels and combining them into the right format. However, I cannot seem to make the Z-5450 understand the format... it always displays "No digital data" and does not output anything.
Now, the documentation is very sparse on this, but states that Dolby Digital is supported, as well as DTS and DTS with 96kHz sampling rate and 24bit samples. The Z-5450 can play digital PCM stereo data, but this only activates left and right speaker (it is possible to set an effect to distribute sound to the other speakers, but this is insufficient for my purpose). I can play digital DVD 5.1 sound by attaching the coaxial cable to a DVD player.
As of now, speakertest -c 6 tries to play sound on all speakers, but only left and right respond. For all other speakers, "No digital data" is displayed on the Z-5450 console. This is consistent with the Z-5450 not able to play six-channel PCM data. However, using -Dplug:a52 and .asoundrc =
pcm.a52 { type a52 } (with various settings)
always shows "No digital data" and no sound output. I had a sample DTS 96/24 file a while ago which was able to activate all speakers, so the data connection is ok. But sadly I have misplaced it; in any case DTS 96/24 support is not what I'd expect in the near future.
Has anyone successfully output Dolby Digital (A52, AC3, ..) data via coax to the Z-5450 or a similar model? I'm using the newest alsa drivers and plugins on an 2.6.11, and the stereo-PCM output has been working for years... but this one keeps bugging me.
Best, Alex
At Tue, 11 Dec 2007 14:22:49 +0100, Dr. Alexander K. Seewald wrote:
I am trying to output Dolby Digital data via coaxial cable to the Logitech Z-5450 5.1 speaker set. Presumably, a52 is the right plugin for this, taking six channels and combining them into the right format. However, I cannot seem to make the Z-5450 understand the format... it always displays "No digital data" and does not output anything.
Now, the documentation is very sparse on this, but states that Dolby Digital is supported, as well as DTS and DTS with 96kHz sampling rate and 24bit samples. The Z-5450 can play digital PCM stereo data, but this only activates left and right speaker (it is possible to set an effect to distribute sound to the other speakers, but this is insufficient for my purpose). I can play digital DVD 5.1 sound by attaching the coaxial cable to a DVD player.
As of now, speakertest -c 6 tries to play sound on all speakers, but only left and right respond. For all other speakers, "No digital data" is displayed on the Z-5450 console. This is consistent with the Z-5450 not able to play six-channel PCM data. However, using -Dplug:a52 and .asoundrc =
pcm.a52 { type a52 } (with various settings)
always shows "No digital data" and no sound output. I had a sample DTS 96/24 file a while ago which was able to activate all speakers, so the data connection is ok. But sadly I have misplaced it; in any case DTS 96/24 support is not what I'd expect in the near future.
Has anyone successfully output Dolby Digital (A52, AC3, ..) data via coax to the Z-5450 or a similar model? I'm using the newest alsa drivers and plugins on an 2.6.11, and the stereo-PCM output has been working for years... but this one keeps bugging me.
Check first whether "ac3dec -C foo.ac3" work to send AC3 data (not on the fly encoding). Try a52 plugin after confirming this works.
(And, I know there are still some bugs with a52 plugin but no time to play with it right now...)
Takashi
On Mon, Dec 17, 2007 at 11:30:56AM +0100, Takashi Iwai wrote:
Check first whether "ac3dec -C foo.ac3" work to send AC3 data (not on the fly encoding). Try a52 plugin after confirming this works.
Does not work with -C, but works with --card=0 - only as a PCM audio signal, sadly, which already works (no digital dolby, only left and right speakers are active). I checked -C --card=0 and all the other settings of ac3dec as well - no success.
(And, I know there are still some bugs with a52 plugin but no time to play with it right now...)
Problem seems to lie deeper...
Best, Alex
At Mon, 17 Dec 2007 22:03:38 +0100, Dr. Alexander K. Seewald wrote:
On Mon, Dec 17, 2007 at 11:30:56AM +0100, Takashi Iwai wrote:
Check first whether "ac3dec -C foo.ac3" work to send AC3 data (not on the fly encoding). Try a52 plugin after confirming this works.
Does not work with -C, but works with --card=0 - only as a PCM audio signal, sadly, which already works (no digital dolby, only left and right speakers are active). I checked -C --card=0 and all the other settings of ac3dec as well - no success.
(And, I know there are still some bugs with a52 plugin but no time to play with it right now...)
Problem seems to lie deeper...
Sounds so. Which hardware and driver is it?
Takashi
On Tue, Dec 18, 2007 at 01:01:53PM +0100, Takashi Iwai wrote:
Problem seems to lie deeper...
Sounds so. Which hardware and driver is it?
* NVidia CK804 (integrated into the motherboard MSI K8N Neo4 Platinum)
aplay -l:
card 0: CK804 [NVidia CK804], device 0: Intel ICH [NVidia CK804] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: CK804 [NVidia CK804], device 2: Intel ICH - IEC958 [NVidia CK804 - IEC958] Subdevices: 1/1 Subdevice #0: subdevice #0
* Alsa drivers 1.0.8-7 (= latest stable version on Debian Sarge) [2.6.11 kernel, Debian sarge]
I used to have a wav-file which played 5.1 audio using these drivers, but have misplaced it. But I think it was encoded into DTS 96/24 (96kHz, 24bit samples) which is IMHO not supported by any plugin. This means that the connection probably works, but the internal hardware Dolby Digital decoder is not happy with the format, right?
Best, Alex
At Tue, 18 Dec 2007 15:52:30 +0100, Dr. Alexander K. Seewald wrote:
On Tue, Dec 18, 2007 at 01:01:53PM +0100, Takashi Iwai wrote:
Problem seems to lie deeper...
Sounds so. Which hardware and driver is it?
- NVidia CK804 (integrated into the motherboard MSI K8N Neo4 Platinum)
aplay -l:
card 0: CK804 [NVidia CK804], device 0: Intel ICH [NVidia CK804] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: CK804 [NVidia CK804], device 2: Intel ICH - IEC958 [NVidia CK804 - IEC958] Subdevices: 1/1 Subdevice #0: subdevice #0
The driver won't work properly for SPDIF I/O on nvidia chipset. It cannot set SPDIF status buts correctly. AC3 requires non-audio bit, and some receivers are sensitive for that. DTS doesn't seem to require it (at least most receivers work).
- Alsa drivers 1.0.8-7 (= latest stable version on Debian Sarge)
[2.6.11 kernel, Debian sarge]
Oh hoo, a stone age version...
Takashi
On Tue, Dec 18, 2007 at 02:14:57PM +0100, Takashi Iwai wrote:
The driver won't work properly for SPDIF I/O on nvidia chipset. It cannot set SPDIF status buts correctly. AC3 requires non-audio bit, and some receivers are sensitive for that. DTS doesn't seem to require it (at least most receivers work).
Do you know of any open-source DTS encoders? Maybe that is simpler than fixing SPDIF I/O... can this even be fixed, or is it a hardware restriction? (i.e. buggy hardware)
Best, Alex
At Tue, 18 Dec 2007 18:02:56 +0100, Dr. Alexander K. Seewald wrote:
On Tue, Dec 18, 2007 at 02:14:57PM +0100, Takashi Iwai wrote:
The driver won't work properly for SPDIF I/O on nvidia chipset. It cannot set SPDIF status buts correctly. AC3 requires non-audio bit, and some receivers are sensitive for that. DTS doesn't seem to require it (at least most receivers work).
Do you know of any open-source DTS encoders? Maybe that is simpler than fixing SPDIF I/O... can this even be fixed, or is it a hardware restriction? (i.e. buggy hardware)
No, I don't know of it.
Takashi
participants (2)
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Dr. Alexander K. Seewald -
Takashi Iwai