Why use SPDIF with HD-PVR?

[wayner]

I have two HD-PVRs and on one I am using SPDIF for audio and on the other I am using analog audio (I couldn't find another optical cable). Maybe I have something setup wrong but the HD-PVR doesn't seem to capture the DD 5.1 from the source content. Therefore are you gaining anything with using SPDIF vs. analog audio cables?

[cat6man]

just 5.1, if you don't care, it doesn't matter which one you use.
usually you need to set 5.1 in the cable box menu (varies by mfr)

[wayner]

I will check this out but I have several boxes Scientific Atlanta 3250HDs, 4250HDs and an 8300HD. By default they have always output 5.1 audio and I have never gone into the boxes to change this so I would be surprised if that is the issue.

Are you sure that you are getting 5.1 audio? I could swear I remember reading other threads that mentioned that you don't get 5.1 audio with the HD-PVR even with SPDIF.

[Rico66]

100% sure. The spdif input get's you DD 5.1 (on all channels that do support this). Very early versions of the hdpvr driver did support only 2.0, but that has been fixed for a long time.
Note that you may need to configure your stbs to output 5.1 as well.

[darcilicious]

Yes, my HD-PVR records in 5.1 when that's what is broadcast; a lot of HD shows however, are still in stereo so it really depends on the individual show/recording.

[wayner]

OK, thanks I will check my STB settings. I know that stuff that should have 5.1 is not coming through as 5.1

[Spectrum]

Here is a quick grab from MediaInfo showing the audio on an HDPVR recording

Audio
ID                               : 4352 (0x1100)
Menu ID                          : 1 (0x1)
Format                           : AC-3
Format/Info                      : Audio Coding 3
Mode extension                   : CM (complete main)
Duration                         : 1h 29mn
Bit rate mode                    : Constant
Bit rate                         : 384 Kbps
Channel(s)                       : 6 channels
Channel positions                : Front: L C R, Side: L R, LFE
Sampling rate                    : 48.0 KHz
Bit depth                        : 16 bits
Video delay                      : -50ms
Stream size                      : 247 MiB (3%)

So it is definitely doing 5.1 channel audio. Are you running recent drivers for the HDPVR? I had horrid lockups with mine and SPIDF until 1.5.7.

[wayner]

Thanks guys - my boxes (both SA3250HDs) were set to "Other" rather than Dolby Digital for Audio Out. With that quick switch I am now getting DD.