Linux Archive

Linux Archive (http://www.linux-archive.org/)
-   Debian User (http://www.linux-archive.org/debian-user/)
-   -   Fwd: ogg quality problem with ffmpeg (http://www.linux-archive.org/debian-user/242392-fwd-ogg-quality-problem-ffmpeg.html)

02-07-2009 09:47 PM

Fwd: ogg quality problem with ffmpeg
 
See Thread at: http://www.techienuggets.com/Detail?tx=27951 Posted on behalf of a User

You should never do is use the ?-acodec vorbis? option of ffmpeg as described here. Instead use ?-acodec libvorbis?. This small change is very important. The former uses the the internal FFMPEG encoder, the latter uses the libVorbis library.

The internal ffmpeg vorbis encoder is about the simplest possible encoder that produces working output. It sounds terrible compared to the reference encoder, as you saw with your own comparison. On a typical musical input the ffmpeg encoder set to 128k produces quality which is obviously worse than libvorbis at 32kbit/sec.

In Response To:

---------- Forwarded message ----------
From: Keith Richie <noway@spam.com>
Date: Sun, Mar 9, 2008 at 1:04 PM
Subject: Re: ogg quality problem with ffmpeg
To: noway@spam.com



On Sun, Mar 9, 2008 at 11:58 AM, asm4 <noway@spam.com> wrote:
> Alex Samad wrote:
> > On Sat, Mar 08, 2008 at 11:57:14AM -0800, David Fox wrote:
> >> On 3/8/08, asm4 <noway@spam.com> wrote:
> >>
> >>> the nominal bit rate shown by xmms or mplayer on out.ogg is 0k and
> >>> average bit rate is 41.7kbps
> > I don't think you can compare bit rates, ogg has better compression than
> > mp3 so 128kb ogg is suppose to sound better than 128kb mp3
>
>
> hi all,
> thanks for the replies. i compared the bit rates of 2 ogg files. one
> created by using ffmpeg (0k nominal, 41k avg), the other created by
> dumping a wav and converting to ogg using audacity (160k nominal,113k avg).
>
>
> >> Is the quality (or lack of) extremely noticable? Ogg is variable rate,
> >> and by "VOB" i'm thinking "movie",
> >> where there may be a large variation of sound sources, compared to for
> >> example a music CD.
>
>
> the lack of quality is extremely noticable. the VOB is indeed a video
> recording of a performance and i just wanted to get the sound. i can
> live with dumping wav and converting using audacity. its just too much pain.
>
> >>
>
> >> Then again, it could be an ffmpeg problem. I don't have any ready vobs
> >> here to test. But I routinely dump audio from other sources (such as
> >> avi) and encode those with ffmpeg, but not to ogg, usually a52 because
> >> I do a fair amount of dvd encoding of avi movies.
> >>
> >>> i have 0.cvs20070307-6 of ffmpeg and this seems to be the latest
> >>> version. am i doing something wrong? or is there a better way of getting
> >> There's a later version 20071206 but it's in the
debian-multimedia repository.
>
>
> i will wait till it makes into unstable. its not a pressing issue.
> thanks for the suggestions.
>
>
> --
>
>
> To UNSUBSCRIBE, email to debian-user-noway@spam.com
> with a subject of "unsubscribe". Trouble? Contact
noway@spam.com
>
>



Try

ffmpeg -i file.vob -vn -acodec vorbis -ac 2 -ab 160k out.ogg

ffmpeg doesn't support multichannel vorbis encoding so the -ac 2 is
needed. You can replace -ab with -aq if you want.


--
To UNSUBSCRIBE, email to debian-user-noway@spam.com
with a subject of "unsubscribe". Trouble? Contact noway@spam.com



--
To UNSUBSCRIBE, email to debian-user-REQUEST@lists.debian.org
with a subject of "unsubscribe". Trouble? Contact listmaster@lists.debian.org

Stefan Monnier 02-09-2009 03:20 PM

Fwd: ogg quality problem with ffmpeg
 
> The internal ffmpeg vorbis encoder is about the simplest possible
> encoder that produces working output. It sounds terrible compared to
> the reference encoder, as you saw with your own comparison. On
> a typical musical input the ffmpeg encoder set to 128k produces
> quality which is obviously worse than libvorbis at 32kbit/sec.

What makes you wonder: why keep it?


Stefan


--
To UNSUBSCRIBE, email to debian-user-REQUEST@lists.debian.org
with a subject of "unsubscribe". Trouble? Contact listmaster@lists.debian.org


All times are GMT. The time now is 02:03 AM.

VBulletin, Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO ©2007, Crawlability, Inc.