Qulaity problems

[Andrewski22]

I have some avi files that I wish to convert to SVCD. I have successfully managed to do this but the result is always very blocky (a grid effect is quite obvious accross the whole picture) when viewed back on a TV screen.

Is this something everyone gets when attempting a conversion of this kind? I am using the quick presets for an XSVCD but I am wondering if there is some kind of manual configuration that would get me a better result? I used to get these files already converted to xsvcd format from my source and they were of a much higher quality than what I have been able to so far produce with FFMPEG although I am sure that the xsvcd files would have been encoded from a similar avi file.

If it is of any help I am using an old G3 imac 500mhz which is slow but does still seem to do the job running 10.3.7.

The details of the file I am trying convert are as follows:

VIDEO: mpeg4, 624x352, 23.98 fps. AUDIO: mp3, 48000 Hz, stereo, 172 kb/s

The details of the end result are as follows:

VIDEO: mpeg-2, size: 352x480, 23.976 fps, 1800 kbps. AUDIO: mp2, 44100Hz, 128 kbps

I'm wondering if these details maybe give some clues as to where I am going wrong. Any advice would be most welcome as I really would prefer to watch these files on my TV rather than my computer if at all possible.

[bucho]

I've noticed the same thing. I've taken a look at VCDs that I created using TMPGEnc on my PC, and they have a much better picture than even SVCDs I've created with ffmpegX. I too always have a 'grid' effect (ie: any diagonal lines show obvious steps). Unfortunately, I don't think this is the fault of ffmpegX, but instead the command line tools operating in the background. I have noticed that using the ffmpeg engine provides better results, but produces less compliant VCDs.

Can anyone else offer any explanations, or better yet, some suggestions?

Major?

[major]

The image quality of ffmpeg engine is better than mpeg2enc engine (and one of the best amongst all encoders). ffmpeg allows to obtain insane quality levels if you use it correctly, and provided the source is not interlaced.

The reason to use mpeg2enc would be to obtain more compliant VCD/SVCDs for picky players (as ffmpeg rate control system has still some flaws). To increase quality with mpeg2enc, you should try to lower the qMin value and use a higher bitrate.

[bucho]

Is there any reason that TMPGEnc would handle interlaced files better (I don't mean to pester, I'm just curious)?

[major]

Currently the Quicktime decoder (used for DV files) always decodes not interlaced. Version 1.0.0 will add support for interlaced decoding & encoding.

[bucho]

Is there a trick I can use to get around this (ie: re-encode video to a different format first)?