Thursday, February 26, 2004

TV Episode Capture to DVD

Switching up my methodology a bit. Previously, I was capturing at 720x480 30fps or 352x480 30fps, encoding at 6000kbps (video) and 256kbps (AC3 audio) which allows me to fit 2 hour-long TV episodes per DVD if the commercials are removed. (Roughly 48min per episode, 96 min per disc. DVD capacity by bitrate table)

However, 6000kbps for half-D1 is over-kill so I've been doing some testing to see how low I can go before I start noticiing artifacts. First off, I've switched completely to half-D1 (352x480 30fps) instead of capturing at full-D1 (720x480 30fps). I tried encodes at 3000, 4000 and 6000kbps and really couldn't see much artifacting even at 3000kbps from a slightly-noisy VHS source. So while I'm not entirely sure that I can go as low as 3000, it's possible that I can go that low or even a bit lower.

My first test is (3) episodes encoded at 3800kbps. This created 3.66Gb of VOBs when I authored the disc, with a best-case of 3.48Gb and a worst-case of 3.78Gb. Assuming disc capacity of 4.30Gb (allowing extra space for PAR2 files), my test used up between 81% and 88% of the available disc space. Even though I told it to encode at 3800kbps for the video, actual average bitrate works out to only be 3500kbps (due to use VBR). With a bit of math (and some hand-waving) that means I could probably boost the video bitrate to as high as 4000kbps (plus 256kbps AC3 audio) and still fit (3) episodes per disc. (Update: the 3800kbps test disc looked fine given the quality of the source material.)

My next test will be to encode (4) episodes for a single disc (192 minutes). This gives me a bitrate budget of 3170kbps, minus 256kbps for audio, leaving me with 2900kbps for video. That seems attainable since my test clips still looked okay at 3000kbps. Tempting, since it will also cut my DVD-R usage even more.

I'm also filtering the video using VirtualDub to remove a bit of noise. The filter is "Smart Smoother High Quality" with settings of "radius 5 threshold 15 amount 254 maintain 5 weighted with difference". I may back that off to threshold 10 to lower the smothing effect just a hair.

posted by Wuphon's at 7:56 PM