ATSC captures w/ffdshow

[mvallevand]

I don't know if it is an issue or not but all my ATSC captures (LiveTV and in-progress recordings) don't show as having the proper 1920x1080 aspect ratio in the ffdshow info, yet if I run them in as Recordings or in GraphEdit they do. My HD-PVR and all the DVB h264 samples I have also show the correct aspect ratio.

I have asked before for an option to have AC3 default for LiveTV (I'm not really sure why this is so tough) to improve the really awful audio sync I have, I guess now I'd also like to ATSC work like h264 and default to 1920x1080 AC3.

Martin

[sub]

This is normal. The app has to tell the demux to create the audio/video pins long before it sees the actual broadcast data, so like all directshow live tv apps, it just uses some hardcoded format blocks. Very few, if any, directshow decoders will pay any attention to the data in those hardcoded format blocks, and will instead use the data they receive.

There is no way to know the real data in advance, and even if you did wait for channel data, it'd be wrong as soon as the user changes channels anyway, so not worth doing.

On the forcing AC3 audio renderer in live tv, you could try the attached patch and <ForcedLiveTVClock>AC3 Audio Renderer</ForcedLiveTVClock> in the <Renderers> section of config.xml.

[mvallevand]

This is normal. The app has to tell the demux to create the audio/video pins long before it sees the actual broadcast data, so like all directshow live tv apps, it just uses some hardcoded format blocks. Very few, if any, directshow decoders will pay any attention to the data in those hardcoded format blocks, and will instead use the data they receive.

Ok, it didn't seem to cause a lower quality image, I thought it might have been the reason for the poor audio, but it seems strictly AC3 related.

On the forcing AC3 audio renderer in live tv, you could try the attached patch and <ForcedLiveTVClock>AC3 Audio Renderer</ForcedLiveTVClock> in the <Renderers> section of config.xml.

Great, thanks a lot that saves 4 seconds of annoyance, which my PC never seemed to get quite right.

Code:

2011-10-12 01:11:53.191    [DEBUG][1]    Static Reference clock set to: AC3 Audio Renderer
..
2011-10-12 01:11:57.159    [DEBUG][1]    audio renderer now AC3
2011-10-12 01:11:57.159    [DEBUG][1]    Dynamic reference clock set to: AC3 Audio Renderer
2011-10-12 01:11:57.159    [DEBUG][1]    Reference clock was already se correctly. No change required.

Martin