HD video encoding

[gobucks]

I am currently ripping my HD-DVD collection to WMV pro in 720p, and throwing them all on a huge external hard drive to play on my xbox 360. It is a complicated process, but I finally have the ripping, demuxing, audio splitting etc. down. When I am done I feed the VC-1 or AVC video to Windows Media encoder via an AVS script, and send it a multichannel (5.1) wav source for the audio.

This all works well and good, but I am curious if my encoding speed is bottlenecked by my hard drive. I have a 3.4GHz e6400 with 2x1GB DDR2 @ 950MHz, 4-4-4-12 timings. My hard drive is a hitachi T7K250 (250GB SATA-II, 8MB cache, 125GB/platter density). On encoding, I get around 25fps on the first pass, and around 8fps on the second pass. I know that transcoding 1080p to 720p is rather CPU intensive, but shoudn't it be capable of going faster than this? If I can find a good deal, I was thinking of getting a pair of 500GB HDDs and running them in RAID 0. Would this make a big difference?

 

[Tristor]

You might be slightly speed limited by your drives, but not significantly. Encoding performance is almost entirely cpu and RAM limited. Switching out your e6400 for a q6600 and bumping it to 3.2 (or 3.4 if you can) would result in a much more significant increase in performance than switching to RAIDed drives of any size or speed. Really though, your speeds are fairly decent. Doing 2-pass x264 on a similar system would be much slower.

 

[gobucks]

thanks for the input - i am considering getting a quad-core CPU, but I'm going to try and wait for penryn and grab one of those - i imagine at 45nm there should be some serious overclocking potential without too much heat, plus it will have larger cache and SSE4 which should help with the video encoding.

so is x264 slower because it is more efficient? I've noticed that AVC seems to take up a lot more CPU resources during playback (I don't have either VC-1 or h.264 GPU acceleration), but I've also noticed that low-bitrate AVC files seem to have much better quality than a similar WMV file - i have several 720p mp4 and mkv files that are 3.5-4GB and are great quality, whereas I aim for a bitrate of around 7500KB/s for WMV, giving files from 6-8GB.

 

[Tristor]

Yes, h264/AVC has much better compressability than other codecs available for HD video right now. The speed at which you encode with x264 is almost entirely dependent on your settings, but with settings targeting a decent quality level and bitrate that matches the quants of your source you will usually see x264 take longer (sometimes 2 or 3 times longer) than WMV Pro. The result will be much higher quality though.