WMC Playback Black Screen/No Audio

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tardyturtle

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WMC Playback Black Screen/No Audio

#1

Post by tardyturtle » Tue Aug 29, 2017 1:15 am

Over the last two days, I have had the issue where playback of shows on certain channels results in a black screen with no audio.

If I stop the recording and restart either my media center or HTPC, I can then tune into the channel live with no playback issues. When I go to play back the original recording in WMC, I still get the black screen with no audio (even after restart), but interestingly, I can open the video in VLC and it plays just fine. So clearly, the issue is with playback in WMC.

I know people have had issues with H.264, but it seems like those issues have all involved no video but audio plays back fine. Does it seem like a codec issue? Any ideas for how to further investigate why WMC isn't properly playing back? I have not made any changes to the system in a while.

Thanks!

Space

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#2

Post by Space » Tue Aug 29, 2017 1:40 am

When the video is playing (black screen), punch in 411<info> on the remote (I believe ctrl-i is the info button on the keyboard).

Right arrow to the last page to see what audio and video codec are detected by the player.

You are correct in that prior instances of the black screen issue had audio but not video, so yours appears to be different.
Those instances are triggered by tuning to a H.264 channel and then to an mpeg2 channel on the same tuner. The black screen only happens on mpeg2 channels (tuning to the H.264 channel triggers the issue, but it never affects the H.264 channel itself).

tardyturtle

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#3

Post by tardyturtle » Tue Aug 29, 2017 10:12 pm

Space wrote:When the video is playing (black screen), punch in 411<info> on the remote (I believe ctrl-i is the info button on the keyboard).

Right arrow to the last page to see what audio and video codec are detected by the player.

You are correct in that prior instances of the black screen issue had audio but not video, so yours appears to be different.
Those instances are triggered by tuning to a H.264 channel and then to an mpeg2 channel on the same tuner. The black screen only happens on mpeg2 channels (tuning to the H.264 channel triggers the issue, but it never affects the H.264 channel itself).
Thanks for the tip! When I checked the recordings, they said video codec was "(not specified)" and audio was Dolby with "0" channels and 0 bitrate. This further supports that it is a codec issue; however, when I tune back to those channels (and others I have been recording on), they show the codec is MPEG2 for live TV. The codec wouldn't change from program to program, would it?

Things seem to be working ok now, so we will see how it goes. It looks like people have had limited success segregating tuners by codec (though it's not entirely clear the codecs are different here). Otherwise, doing a fresh restart seems to help, so maybe scheduling a nightly restart? Any other suggestions?

Space

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#4

Post by Space » Wed Aug 30, 2017 12:07 am

If you go to that info page on each channel, it will tell you if it is mpeg2 or h.264. If you view/record from any h.264 channels and then later view/record an mpeg2 channel, the issue you are having could very well be the same issue as black screen with audio. Although I haven't seen anyone else report that they are also getting "no audio".

Segregating tuners by codec is one solution, but is really only practical if you have extra tuners that are not usually in use. If you only have 3 tuners, for instance, and you regularly record 3 shows at the same time, and they are all mpeg2, then you will have a problem dedicating one of those tuners to h.264 channels. But if you have 6 tuners and normally only use 3 or 4 at the same time, then dedicating 1 or 2 to h.264 seems like a workable solution.

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