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WMC size of HD recordings

post #1 of 8
Thread Starter 
I'm about to go from analog TV to digital HD and am concerned by how much more space HD video will take as I might need to get a bigger hard drive.

Currently, 1 hour of analog TV recording takes 1.4 GB at the bitrate I set, how much should I expect 1 hour of HD video to be? I also think I heard it depends on if it's broadcast in 720p or 1080i/p, is that correct and if so how much can I expect 1 hour at each resolution to take?

I will be capturing with a Hauppauge Colossus in case that makes a difference.

Thanks
post #2 of 8
Half hour shows vary between 2.5-4gb (depending on compression/network). You can double that for hour shows.

Briefly looking at my list of recordings, it appears shows on CBS are among the largest. That makes sense since they're 1080i
post #3 of 8
In the general interest of nitpicking, you'll actually be recording analog video outputs from your digital cable box with the colossus. It should still output 1080i and ac3 passthrough audio (not entirely sure about that part but I read it from the colossus website)

As NNate said varies with channel. ESPN is 720p on Comcast while Comedy Central is 1080i. Both are MPEG2 video with AC3 audio. Typical 30min shows are ~3 GB for me
post #4 of 8
Quote:
Originally Posted by Dark_Slayer View Post

In the general interest of nitpicking, you'll actually be recording analog video outputs from your digital cable box with the colossus. It should still output 1080i and ac3 passthrough audio (not entirely sure about that part but I read it from the colossus website)

As NNate said varies with channel. ESPN is 720p on Comcast while Comedy Central is 1080i. Both are MPEG2 video with AC3 audio. Typical 30min shows are ~3 GB for me

Not to nitpick your nitpicking, but since he'll be capturing an analog stream with the Colossus, I don't think the bitrate should change at all from channel to channel, since the card will be recompressing the video on the fly. I seem to remember reading that there is a setting in the Hauppauge software where you can adjust the capture bitrate and change from CBR to VBR.

Unless I'm mistaken the channel to channel variation you're referring to is if you're copying the stream, unmolested, from the provider.
post #5 of 8
Direct recordings from the tuner, not from capture device are maxed out by 20 Mbps, per the ATSC/QAM specifications.

Most of the broadcasts are not even half of that, because they have multiple sub channels.

We average about 10 GB per 1 hour of raw HDTV stream directly from the tuner.
post #6 of 8
Quote:
Originally Posted by ajhieb View Post

Not to nitpick your nitpicking, but since he'll be capturing an analog stream with the Colossus, I don't think the bitrate should change at all from channel to channel, since the card will be recompressing the video on the fly. I seem to remember reading that there is a setting in the Hauppauge software where you can adjust the capture bitrate and change from CBR to VBR

I can't say for sure, but if anything were recompressing the video on the fly . . . I would think it was the STB prior to the component video outputs rather than the colossus during it's capture-passthrough process
post #7 of 8
Quote:
Originally Posted by Dark_Slayer View Post

I can't say for sure, but if anything were recompressing the video on the fly . . . I would think it was the STB prior to the component video outputs rather than the colossus during it's capture-passthrough process

Somebody correct me if I'm wrong, but I don't think there is such a thing as a compressed analog video stream. (at least not in the same sense we're talking about here) The component video is an analog stream that has been decompressed by the STB. The Colossus then captures and re-encodes/recompressed the analog stream back to digital.(H.264 iirc)
post #8 of 8
No, sounds right. To be fair, I did say "think" . . . but I don't know what I was thinking smile.gif

Makes sense . . . STB decompress -> Component -> Colossus capture/encode/compress -> h.264/mpeg2/etc (whichever one it uses). Thanks for keeping me honest
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