Avidemux Forum

Avidemux => Windows => Topic started by: todd92371 on April 03, 2013, 03:07:21 PM

Title: How to save and not degrade quality?
Post by: todd92371 on April 03, 2013, 03:07:21 PM
Hello,
This is a great program. I am bringing in mp4 hd videos from camera. Alot of time I just clip and save without messing with the native data (copy). But, I was wondering how one can retain the quality when you save it after doing things like filters and more indepth editing. In other words, what settings ensure the mp4 will not degrade in its export process to another mp4. I don't have to worry about this when I do a simple video copy and save.

thanks so much,
Title: Re: How to save and not degrade quality?
Post by: Jan Gruuthuse on April 03, 2013, 05:59:01 PM
make a test video for about 1 minute. Try with Mpeg4 AVC (x264), configure Rate Control (CRF) quality 20, see if that works for you? If not lower this setting until it is workable for you.
There will be always some degradation when processing compressed video and re-encoding!
Title: Re: How to save and not degrade quality?
Post by: xyzuvw on April 04, 2013, 03:26:31 PM
todd92371
If I am not mistaken, the Constant Quantiser mode with quality 0 codes without loss. But it concerns only video.
Title: Re: How to save and not degrade quality?
Post by: Jabberwockxeno on April 06, 2013, 10:20:10 PM
Quote from: Jan Gruuthuse on April 03, 2013, 05:59:01 PM
make a test video for about 1 minute. Try with Mpeg4 AVC (x264), configure Rate Control (CRF) quality 20, see if that works for you? If not lower this setting until it is workable for you.
There will be always some degradation when processing compressed video and re-encoding!

Isn't x264 lossless, though?

Title: Re: How to save and not degrade quality?
Post by: styrol on April 06, 2013, 11:08:01 PM
No, it's certainly not.
Title: Re: How to save and not degrade quality?
Post by: Jabberwockxeno on April 06, 2013, 11:51:11 PM
Quote from: styrol on April 06, 2013, 11:08:01 PM
No, it's certainly not.

I thought it was.

Are there any losless video compression formats out there then that most programs accept?
Title: Re: How to save and not degrade quality?
Post by: Jan Gruuthuse on April 07, 2013, 04:01:06 AM
Not yet I suppose: Video codecs (http://en.wikipedia.org/wiki/List_of_codecs#Video_codecs)
Title: Re: How to save and not degrade quality?
Post by: Lilly on April 24, 2013, 01:34:43 AM
Quote from: xyzuvw on April 04, 2013, 03:26:31 PM
todd92371
If I am not mistaken, the Constant Quantiser mode with quality 0 codes without loss. But it concerns only video.
Yeah crf 0 or qp 0 = lossless (High 4:4:4).
I used it for testing a couple of times too, but the videosize is still very large (smaller than other lossless solutions ). So except for something temporary I wouldn't know what to use lossless avc for anyway. For archiving purposes decoding lossless avc is not well supported (x264 is the only encoder capable of lossless avc coding - so some [most?] decoders have trouble supporting it).

For a lossless feeling crf 18 is enough.

Usually I use lagarith for lossless compression but that (de- and encoding) works only in applications that do use system codecs. Tools with inbuilt libraries like Avidemux can't decode nor encode it. Avidemux offers Huffyuv though, another lossless codec... format... whatever.
Title: Re: How to save and not degrade quality?
Post by: styrol on April 24, 2013, 05:07:46 AM
QuoteFor a lossless feeling crf 18 is enough.
Lossless feeling and lossless codec is not the same.

Quotex264 is the only encoder capable of lossless avc coding - so some [most?] decoders have trouble supporting it).
x264 encoder produces h.264 video, so each h.264 decoder (QuickTime, Microsoft) should decode it.