Realtime DivX encoding with 1Ghz CPU?

[Joxx]

Hello,

I have a PIII 500Mhz. I can encode HufYUY AVI files in 352*288 to DivX and the sound to mp3 in about 15fps.

An 1GHz CPU should, I think, do 30fps encoding with an already recorded AVI.

Does this mean that I should be able to encode YUY2 with sound to DivX in realtime (PAL=25fps)? Or is realtime encoding slower than non-realtime (with already recorded AVI)?

Is the quality of a realtime encoded DivX file equal to a non-realtime encoded AVI?

[Eric VanHeest]

On a Celeron 566 clocked at 850, I've can capture to 352x240 to the DivX video codec in realtime with relative ease (NTSC rather than PAL, but the datarate is the same). I've never tried encoding the sound at the same time, as I always want to do noise reduction and normalization on the audio before compressing it, but if I am simply compressing audio, I can compress a 60-minute 44 kHz PCM file to DivX 64 kbit audio in about 3 minutes, so I imagine it might work in realtime along with the video.

I can -almost- capture at 352x480 to DivX video in realtime on the 850 MHz machine; it gets around 28 frames/sec. However, I don't know if the interlaced resolution causes any extra problems for the DivX compressor. I can't use the deinterlacing filter while capturing; it isn't anywhere near fast enough.

Note that converting a HuffYUV avi to DivX involves a good amount of processor effort on the part of the HuffYUV decompressor as well; real-time compression to DivX would not involve that overhead, so it would probably actually work -better- than a prerecorded AVI. I would recommend continuing to use HuffYUV if you plan to do any editing of the resulting video whatsoever, however; the quality and ease of editing a non-temporally-compressed video (and lossless to boot) is much higher.

[Dr Mordrid]

I agree.

Realtime software compressed video is limited in data rate to what can be captured without drops. For my PIII/850 system this peaks out at 352x480 to about 2600 kbps using DivX, depending on the content.

That's not too shabby, but it pales in comparison to to the quality you can achieve capturing 704x480 HuffYUV and DivX encoding that at 4000-6000 kbps.

Dr. Mordrid


[This message has been edited by Dr Mordrid (edited 15 August 2000).]