AVI to DVD: DVD's get too compressed

[vince.nl]

Hi,

Most of the times when I convert an AVI (Divx or Xvid) to DVD, and set the bitrate so that it just fits a 4.3 GB DVD, the result is a VIDEO_TS folder of just 2GB, and a .mpg of the same size, resulting in a much lower quality than I wanted.

I've checked and doublechecked all settings everytime, and I'm sure the bitrate is ok when I click 'encode'. (I let ffmpegX calculate the bitrate by time and discsize)

Anyone knows a solution for this problem?

cheers,


Vincent

[guns1inger]

If you are setting up the encoder correctly, and using the correct bitrate, then you will get the size you calculated. If you don't then either you have not set up the encoder correctly, you have mis-calculated the bitrate, or the encoder is ignoring your instructions.

A common mistake is to set a bitrate, then request constant quality, instead of a constant bitrate. When starting out with highly compressed source, such as Xvid/Divx avi files, CQ mode often produces lower quality mpegs because the source does not warrant high quality.

Of course, if you provide a lot more detail on exactly how you set up your encoder you might get a more specific answer.

[vince.nl]

Hi, thanks for your reply, but I doubt that;s it, because I've never set the CQ-setting.

Here is an overview of my used settings for a certain movie:

VIDEO
codec: MPEG2 (ffmpeg)
97min in 4300MB > bitrate 5815 kbit/s
size: 720x480
framerate: PAL (25)

AUDIO
mp3 @ 312 kbit/s, 48000Hz, CBR

FILTERS
just a .srt subtitle file, no custom settings

OPTIONS
[V] high quality
[V] two-pass
encoding profile: dvd
author as: DVD (VIDEO_TS)


I hope you can get something from this info.

thanks,


Vince

[guns1inger]

The numbers look right, except for the framerate. Unless you are converting PAL to NTSC and using pulldown to correct the framerate, you have a contradiction. NTSC DVD is 720 x 480 at either 23.976 fps with pulldown, or 29.97 fps. PAL is 720 x 576 @ 25 fps. You may have to adjust your resolution or framerate to correct this. (Of course, if you are using DGPulldown to correct the framerate for format conversion then your numbers are OK)

Otherwise the numbers appear correct. This would point to a possible issue with ffmpegx, although as I don't use it, I would n't know where to start looking.

[vince.nl]

OK, I'll look into it with your info...

You're saying you don't use ffmpegX, do you prefer another way of converting avi to dvd? (on mac)

thanks again,

vince

[tinker]

Beside your framerate, your audio is mp3, not compliant with DVD specifications. Either AC3 or LPCM at 48 kHz. For NTSC DVD audio standard is AC3.

[guns1inger]

Good call. Didn't even look at the audio beyond the bitrate.