disappointing dvd encode :-( help

[balkandvb]

I encoded a 3ivx movie file (dont worry, its not copyrighted) into ffmpegx (latest version) , burned the dvd, and got a low quality encode. In low quality i mean bad,thin, audio with no punch, and video on fast action scenes gets errors by cyan-type colored blocks coming out of nowhere. I wonder what i can possibly do to avoid this? Any options i can turn on? Btw i used the preset dvd ffmpegx option. I also check encode with quicktime and the letterbox option (the movie is 1.85:1)

[alph]

Did you open the movie in FFMPEGX first, and then select the preset? If not the size, bitrate and other variables could have been changed. With the information you provide this is the only thing I could see going wrong other than your source file having some quality problems to begin with.

Cheers
Alph

[balkandvb]

yes, i did drop it in first, and then i did what i have to do. These errors only appear on TV, incidentally... when i used apple's dvd player, i didn't see them.

Is the mpeg-2 ffmpegx option supposed be a "high quality" mpeg 2 encode as opposed to the mpeg2enc?

There is no reason why these digital blocks should be appearing on fast moving action scenes. iDVD encodes flawlessly but does not let me input a file longer than 90 mins.

Will upping the bitrate help? I hit "best", and ffmpeg calcuated about 2994 to be best quality.. should the videobitrate be 4000? it was blue..

[miksu]

Qmin setting used (lowest rate for VBR)? Makes sometimes big difference IMHO.

I usually use also HQ-option, 4 motion vectors, Trellis quanization and Qpel-options, as they are supposed to improve quality. Takes more time, but it's speedy enough even with my humble Sawtooth running at 450MHz.

[alph]

If this is only occurring on your TV, then it could be that your DVD player does not like the less than constant bitrate that ffmpeg creates. In my view, ffmpeg provides slightly better quality than mpeg2enc, but it's not a truly constant bit rate encoder. High action can cause data-rate spikes. You should try using mpeg2enc to see if your dvd player still produces those errors. Mpeg2enc is slower, but turning off decode with quicktime can speed things up a little if you don't require letterboxing.

Increasing the bitrate beyond "best" has never visibly increased quality for me. I seem to remember major saying adding up to 10% more can in some cases help, but beyond that that little is gained.

Alph

[balkandvb]

miksu: my qmin was 2 and max was 20 and i had hq on only.

aplh:

That could be the explanation. I will try mpeg2enc, so should i just check the "constant bit rate mark?"

And i do have to letterbox, but in mpeg2enc i dont have to have decode with quicktime checked for the letterbox option to be checked.

and also what is your take on the audio? I heard ffmpegx doesn't normalize correctly. Should I use a.pack for encoding to ac3 and then make a video_ts out of the ac3 and m2v file?

[alph]

I believe the preset turns on that constant bit rate check box. Just drop the file, select preset and the only changes I make are to video (click best) and audio bit rates. I'm no expert on mpeg2enc, but I seem to remember some weirdness when trying to letterbox without quicktime. Best advice is to test it: if you have a DVD-RW, just use a 10 minute video clip and try different configurations.

If using mpeg2enc still gives you those artifacts my conclusion would be that there is something in the original source that is not decoding properly with ffmpeg. When using mpeg2enc, if you uncheck both decode with quicktime and mplayer, ffmpeg decodes as was probably the case when you encoded with ffmpeg if you had unchecked decode with quicktime.

Alph

[balkandvb]

last time i encoded with ffmpeg but i also had quicktime and letterbox on.

And thats a good idea, instead of wasting dvd-rs i'll get a dvdrw to do experiment.

[alph]

After my previous post here I did a little testing with the various decoders under DVD mpeg2enc: quicktime, mplayer, and, if both off, ffmpeg.

-Quicktime and ffmpeg are about the same speed.
-ffmpeg generated errors, and even failed once
-mplayer worked fine, but was slower than either of the other 2.

From this my conclusion would be that the preset, not that I would ever doubt major, is correct in that decode with quicktime is the best option with mpeg2enc.

Alph

[balkandvb]

thanks.. ill try and make an encode with mpeg2enc and quicktime box checked. thanks alph.

[balkandvb]

dammit. mpeg2enc is not working like it should. It gives me a error at the end and it encodes most of the file but it cuts off the end. Heres the last few lines of the info (i have encode with quicktime checked and letterbox):

Input #0, wav, from '/Users/druzetito/Desktop/newdusttest/dust3ivx.wav':
Duration: 00:01:59.2, start: 0.000000, bitrate: 1411 kb/s
Stream #0.0: Audio: pcm_s16le, 44100 Hz, stereo, 1411 kb/s
Output #0, mp2, to '/Users/druzetito/Desktop/newdusttest/dust3ivx.copy':
Stream #0.0: Audio: pcm_s16le, 44100 Hz, stereo, 1411 kb/s
Stream mapping:
Stream #0.0 -> #0.0
Press [q] to stop encoding
size= 18176kB time=105.5 bitrate=1411.2kbits/s
size= 20548kB time=119.3 bitrate=1411.2kbits/s
ffmpeg version 0.4.9-pre1, build 4736, Copyright (c) 2000-2004 Fabrice Bellard
configuration: --enable-mp3lame --enable-gpl --disable-vhook --enable-ffplay --disable-ffserver --enable-a52 --enable-xvid --enable-faac --enable-faad --enable-amr_nb --enable-amr_wb --enable-pthreads
built on Jan 7 2005 02:34:06, gcc: 3.3 20030304 (Apple Computer, Inc. build 1666)
video:0kB audio:20548kB global headers:0kB muxing overhead 0.000000%
INFO: [mplex] mplex version 2.2.2 ($Date: 2003/05/13 20:27:15 $)
INFO: [mplex] File /Users/druzetito/Desktop/newdusttest/dust3ivx.m2v looks like an MPEG Video stream.
**ERROR: [mplex] File /Users/druzetito/Desktop/newdusttest/dust3ivx.copy unrecogniseable!
**ERROR: [mplex] Unrecogniseable file(s)... exiting.

it seems its creating some .copy file for no reason. dunno why.

[alph]

It seems your video got encoded, and it looks like your audio may have as well. It seems to be failing on the multiplexing. You used the DVD mpeg2enc preset?

If you have the elementary streams, the .m2v and .mp2 files, try to mux and author from the Tools tab.

Alph

[balkandvb]

yes it did get encoded but it did not encode the WHOLE file. Some video is missing at the end.

I did use the mpeg2enc preset.

I dont need to have it muxed, I had passthru and checked off audio i just need the m2v file to use with another ac3 file.

[balkandvb]

nevermind. You gave me a hint thanks. Since i wasn't telling it to encode audio it was annoyed. And it didnt clip off at the end.

Now its time to see how it will look on the tv.

[balkandvb]

SUCCESS!! Thank you alph for all your help. No errors in even the most actionfull scenes. mpeg2enc is the way to go for me. I found the way to fix the low audio, I just used a.pack, what a great program that is.

[major]

When using mpeg2enc, if you uncheck both decode with quicktime and mplayer, ffmpeg decodes

Just for completeness, there is a further case here if the source is a VOB file, then mpeg2dec is used to decode (quite fast but mostly reliable for PAL).