ASF to Divx, similar bitrates?

[bigMach™]

I want to convert a heap of asf files to divx, using tmgenc xpress. The asf files are pretty low quality, so I was just wondering is there sort of like a way to work out what bitrates are needed to not make the divx files look worse than the asf files, but at the same time, not to make the divx files unnecessarily large?

these are the average file details of the asf files:
Video
Format : VC-1
Codec ID : WMV3
Codec ID/Info : Windows Media Video 9
Codec ID/Hint : WMV3
Duration : 50mn
Bit rate mode : Constant
Bit rate : 448 Kbps
Width : 320 pixels
Height : 240 pixels
Display aspect ratio : 4/3
Frame rate : 30.000 fps
Resolution : 24 bits
Bits/(Pixel*Frame) : 0.194

Audio
Format : WMA2
Codec ID : 161
Codec ID/Info : Windows Media Audio 2
Description of the codec : Windows Media Audio 9.1 - 64 kbps, 44 kHz, stereo (A/V) 1-pass CBR
Duration : 51mn 17s
Bit rate mode : Constant
Bit rate : 64.0 Kbps
Channel(s) : 2 channels
Sampling rate : 44.1 KHz


I already tried a 5min clip of one of the files(no audio), left everything unchanged in tmpgenc (using HT profile), and made bitrate 500kbps. It turned out 21MB, and the quality looked a tad less, so maybe I should make it slightly more.
It also took about 1min to encode, so am I right in thinking that one file as above, would take 10mins to encode and be roughly 200MB at 500kbps. A Bit longer and larger if I up the bitrate? Is that time look normal or is it way too long for the 5mins and config used for encoding?
Because I tried vdub to see if it was quicker, but it wouldn't encode, says missing codec (even though its installed), but if the tmpgenc time is ok, I'll stick with it.


thanks.

[jagabo]

Use 1-pass quality-based encoding in Divx. Pick the quality you want (target quantizer) and encode in a single pass. You always get the quality you ask for. The file will come out whatever size is necessary to achieve that quality. The lower the quantizer the higher the quality. I find 3 to be a good compromise of quality vs size.

Encoding time will vary depending on frame size, frame rate, and settings chosen in Divx. The major Divx setting that effects encoding time is Codec Performance, Encoding Mode. Going higher than Better Quality is mostly a waste of time. With bitrate based encoding multipass VBR will deliver better quality than 1-pass CBR but will take twice as long.

[jman98]

You could use Dr. Divx or AutoGK to encode to Divx. I really don't understand why some people use TMPGenc to encode to all sorts of crazy things like Divx and WMV. TMPGenc was originally designed only to encode to MPEG-1 and MPEG-2 and putting all this other "functionality" on top of it hasn't made it any better. In fact, it's actually starting to become a lot like Nero - jack of all trades, master of none.

[bigMach™]

well I set it for 1-pass constant Q, but I set it to 4(before I read replies), and the encoder to "better".
the file above took 16mins to encode, and ended up 200MB (the original asf is 190MB).
It seemed ok, not better, not worse, might try CQ 3 next, and stick to one of them.

Just another thing, the videos have a black bars at the top and bottom. If I did some cropping or masking, would the encoder then just apply to the picture, instead of the bars as well, and produce better quality?


thanks again.