Is there an MPEG2 encoder minimum bitrate?

valnar wrote on 7/29/2002, 5:54 AM

I'm trying to find that magic number for 1/2D DVD creation (352x480) that will work with the Mainconcept encoder. If I lower the bitrate (either CBR or VBR) to around 3,100,000 (or higher) it works fine. If I lower it to around 2,500,000, then it'll go for a few hours, get about halfway done or so, then the program will exit completely. I'll come back to my PC and it will be showing Windows, like VV3 never ran. It just exits and never finishes the MPG file! The file size is usually around 900MB+ or so when it konks out.

Any ideas?
Robert

Comments

riredale wrote on 7/29/2002, 1:28 PM

Try encoding a short segment to see how low a bitrate the MC encoder can deliver.

There is nothing in the DVD spec that I can find that specifies a minimum bitrate for MPEG2 video. Jim Taylor's book, "DVD Demystified," specs 1.5Mb/sec (for full 480x720 resolution) but says in a footnote that this is not an absolute limit, just that there is no reason to go lower due to poor quality.

RichMacDonald wrote on 7/30/2002, 2:34 PM

Make sure you are working with the latest release.
The first VV3 version had a bug, where, if you used a non-standard bitrate, a
memory leak would build until VV quit without warning.

When you start the render, do a ctrl-alt-del and watch the memory usage of VV.
If it climbs continually, that is the problem.

Although the error was only verified on the nominal and maximum bitrates.
No one ever tested the minimum bitrates, afaik.