Can’t manage to get desired bitrate using DivX.

[Alexander S]

Can’t manage to get desired bitrate using DivX.
I assign the parameters for Dr. DivX or DivX codec in Virtual Dub to encode MPEG-2 file (544x400Resolution, average bitrate 1400 kbits/sec, 25.000 fps), but each time the bitrate is different. Sometimes it is more, sometimes it is less then desired. But even if I manage to get it artificially (for example I assign, say, 1416kbits/sec and get the required 1400 kbits/sec), still when I am trying to combine 2 avi.files (glue them) in Virtual Dub, it fails. It reads something about different video formats. Which parameters beside resolution, bitrate and fps should I consider to combine 2 avi.files in one? What is the way out?

[AsTimeGoesBy]

Hi - I guess it's quite normal that when using DivX the resulting bitrate deviates slightly (<5%) from the bitrate you have choosen. I think this depends strongly on the content and on the encoding mode itself.
But if you had encoded the same video serval times and the resulting bitrate would be in each case different - what would be strange!


Joining avi is sometimes a bit tricky, because avi is generally only a 'cover' that may contain a lot of video types.
So some characteristics must be identical when joining two avi files in VirtualDub:
- codec (2x divx or 2x indeo or 2x uncompressed or ...)
- dimension (width x height)
- frames-per-second
- video color depth (?)
And additionally if an audio stream exists:
- audio codec (2x mp3, 2x wav pcm, ...)
- audio sampling rate (kHz)
- audio bitrate (?)

As you see, i haven't mentioned the video bitrate. - Because none of the divx avi files i have ever joined have had identical bitrates.
And for the other characteristics... well, maybe there are some hints to force joining in some cases but that is beyond my knowledge. Better use the serach function 'joining avi'... ;)

[stephanV]

it also depends on the pass mode... i think 1-pass will be less accurate than multipass (although ive never really tried it)

anyway, joining mpeg4 files in VirtualDub is screwed... its very likely not to work. its best if you join the files before encoding with for example AVISynth.


- codec (2x divx or 2x indeo or 2x uncompressed or ...)
- dimension (width x height)
- frames-per-second
- video color depth (?)
And additionally if an audio stream exists:
- audio codec (2x mp3, 2x wav pcm, ...)
- audio sampling rate (kHz)
- audio bitrate (?)

Video color depth in MPEG4 is always the same, but is indeed something to keep in mind.

indeed the audio bit rate should be the same, and i can add the number of channels (mono, stereo) to that list :)