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rambling about encoding

Well, I’ve finally settled into an encoding configuration that is presentable enough to use on most everything. It’s not the best, but it’s acceptable, and looks good on my TV, and I’m tired of not doing any encoding lately … so I’m going with it.

I actually did end up using mencoder as the default encoder instead of transcode. Well, it’s the default anytime there is something odd like variable framerate or transcode just can’t get it quite right. If the framerate is standard on it though, I run a two-pass encode on transcode instead.

I actually did run into a funky bug either with mencoder or mkvtoolnix (Matroska tools), but I’m not sure which one it is. The DVDs are encoded at 720×480 resolution, or a 1.5 ratio, but whenever I would encode them … mencoder would save them as a 1.33 ratio. The AVI would play fullscreen, but when I wrapped it into Matroska, it probably used the incorrect ratio, and rescaled it on playback so now I had black bars at the bottom and top.

I tried using -vf dsize=1.5 for a quick hack with mencoder to force it to 1.5 instead of 1.33, and I could have sworn that worked, but when I tried it later it wasn’t. So, instead, I’ve resorted to the less friendly but still functional option of rescaling the video to 640×480 instead. Not really a big deal since I’m not moving it around that much, but still not desirable. I think that’s probably the reason now that transcode would chop off a few pixels on each side when encoding, was to make sure that the aspect ratios were correctly calculated. I guess.

Another thing that’s interesting is that I could rescale it down to 320×240 if I wanted to. I’m not sure, but I think that’s what my television’s highest resolution is anyway (no HDTV for me). The video looks just as good, as far as I can tell. The only problem (there’s always something) is that mencoder always chooses to ignore my bitrate options that I’m telling it to use (2200) and encodes it at 700 kbps instead, which is pretty annoying. Even at 2200 and rescaling to 640×480, it still only encodes at around 1800. I don’t know what’s up with that. I was looking at the mailing lists yesterday, and I couldn’t find any way to force mencoder to use CBR with XviD. Bleh. Another reason I prefer transcode, right there. I eventually did find out though that you pretty much have to either double or quadruple the bitrate in your config file or arguments for it to actually downgrade to where you really want it.

I’ve also started playing with some video filters on mencoder. The cartoons still look much better with transcode, but that’s most likely because I’m passing it through three filters. Right now I’m trying to find the mencoder equivalents. It’s not all that big of a deal though, and I’m just glad I’ve found something that gives pretty good acceptable quality for now. The live-action shows are easy to encode, its the cartoons that you really notice the problems because of all the action and the cool colors. I’m planning on coming back to doing more research when I’m all finished encoding, but for now I think I’m finally set. 🙂

One Comment

  1. mattm mattm July 27, 2006

    I’ve never had any problems with mencoder’s aspect ratio. Have you speciying -autoaspect on the command line when encoding?


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