Audio sync

[scdawson]

Just wondering, does the audio sync adjustment work? If find that the audio is delayed a little too much on most programs -- around 60ms. I'd like to adjust it however when I bring up the panel to adjust (see pic) it it seems to have no effect, whether advancing it or retarding it. Or perhaps I'm doing it wrong. (Using T4, latest firmware)

[Grumpy_Geoff]

Previously reported as not working - "audio sync function not operative"

[prl]

I had a bit of a dig around in the code, and it appears that only the audio stream types AC3 and PCM have the facility to change their audio delay.

[scdawson]

Ah, thanks. Seems a pity to have an elaborate control screen for something that doesn't work.

It it's not adjustable, then the standard setting probably needs to be changed. I'll do some experiments to work out precisely how far it is out with standard programming.

[prl]

I didn't say that it doesn't work. It should probably be clearer about when it does work, though.

[scdawson]

Sorry, that was my belated reply to Grumpy which I wrote, at point X, and forgot to press key for until point X + 2 hours. Do you think it could be changed to work with MPEG2 audio as well since that's the majority of stations.

[prl]

It looks like a Linux driver-level thing (which may reflect hardware capability).

Changing the delays for AC3 and PCM respectively writes the delays into /proc/stb/audio/audio_delay_bitstream and /proc/stb/audio/audio_delay_pcm. There are no other /proc/stb/audio entries that look like they are delay controls for any other audio types. I only looked on the T4, but the upper level firmware also restricts the choice, though that is easier to change than at the driver (or hardware) level.

[prl]

Sorry, that was my belated reply to Grumpy ...

Then my answer is directed to Geoff

And the function does in fact seem to be likely to be operative, for certain special values of "operative".