Also sprach Ari Huttunen zu "01.12.2003 22:55" Anno Domini:
> Well, I shot the TV with a digital camera and put the result here:
> http://heechee.blogsite.org/tvshot.jpg
>
Ok, visible MPEG macro blocks! This means to high quantisation. You can
get comparable results, if you use a DVD shinking tool with its highest
shrinking rate!
BTW: Around the text, you can also see other artefacts, which seem to
come from encoding/deinterlacing.
> The shot is a small part of a frozen video. The blockines is apparent on
> the left side.
> This looks worse than in reality, naturally.
>
> As to your questions about encoding and playing:
>
> ffmpeg -i 001.vdr -y -hq -b 1800 -ab 160 -f avi -vcodec mpeg4 -acodec
> mp3 -qmax 10 -4mv -deinterlace -pass 1 foo.avi
> ffmpeg -i 001.vdr -y -hq -b 1800 -ab 160 -f avi -vcodec mpeg4 -acodec
> mp3 -qmax 10 -4mv -deinterlace -pass 2 foo.avi
>
Ah, you use ffmpeg directly. I prefer using it through mencoder, which
has more video filters, input capabilites, ... That way, changing to the
commercial DivX version is also only replacing one or two commandline
arguments.
> logger: *** Starting mplayer.sh Version 0.8.4
> logger: *** DEBUG: Variable CFGFIL has value
> "/usr/local/bin/mplayer.sh.conf"
> logger: *** Use Option USERDEF at your own risk!
> logger: *** Option DVDFiles not set correctly! You will not be able to
> play VCD/DVD
> logger: *** INFO: Source Video has Resolution of 720 x 576 ...
> logger: *** INFO: For Sqare Pixels we would scale to 1024 x 819 ...
This line is somewhat strange. I just ran some quick tests and all my
AVIs printed out the same resolution as in the line above. Maybe this
comes from a aspect ratio encoded into the MPEG4-video stream by ffmpeg
(I know ffmpeg can do this, although noone else beside ffmpeg (and
mplayer) can use it). Can you set DEBUG="true" in your mplayer.sh.conf.
This will give much more verbose output of the mplayer.sh script.
> MPlayer 1.0pre2-3.2.2 (C) 2000-2003 MPlayer Team
[...]
> PLAYBACK STARTED
> VDec: vo config request - 720 x 576 (preferred csp: Planar YV12)
> VDec: using Planar YV12 as output csp (no 0)
> Movie-Aspect is 1,33:1 - prescaling to correct movie aspect.
> SwScaler: using unscaled Planar YV12 -> Planar YV12 special converter
> VO: [mpegpes] 720x576 => 768x576 Mpeg PES
>
The complete mplayer output seem correct to me, I cannot see any hint,
what's going wrong from it!
>
>> I use the (propritary & non-free) DivX libraries from divx.com for
>> encoding to MPEG4, as I made the experience, that they produce a better
>> quality at the same bitrate as ffmpeg. With a bitrate of about
>> 1500kbit/s and a resolution of up to 1024x576 I never had any block
>> artefacts in the MPEG4 files.
>>
> Hmm, that's an idea.
As I said above: Using mencoder for transcoding makes the switch between
divx & libavcodec quiet easy. Maybe just try and check, if the problem
disapears.
>> What are the "other effects", shortly?
>>
> Well, edges had noise in another scene, but I noticed that was actually
> there to begin with, and
> after postprocessing there was bluriness where there used to be blockiness.
>
That's obvious: You cannot add information lost to hard encoding or
error (= sharpen picture). But you can try to hide it from the user view
(= blur). That's why I don't like post-processing filters: I think they
make it even worse, than it is. One exception is deinterlacing, but only
for interlaced material!
> Gmplayer on computer screen looked quite a bit like the TV output, but
> better. With Xine
> the whole blockines disappeared when postprocessing was set to full.
> Couldn't do more than
> enable/disable postprocessing in gmplayer, though.
>
If (g)mplayer has the same errors on the computer screen, it seems, that
you problem has nothing of at least nearly nothing to do with encoding
to MPEG1 but with your source material: the encoded AVI.
> Well, I guess I partly messed it up because the 2500 kbit/s was not
> deinterlaced, and there's
> interlaced text scrolling upwards. But still, I found that there was
> practically no difference
> between 1800kbit/s+deint, 1800kbit/s(noint) or 2500kbit/s(noint).
>
Is your source MPEG really interlaced? Otherwise you drop useful and
maybe also important video information for nothing! Interlacing can
hardly be recogized on y-axis movements but on x-axis movements.
> That appears slow. The ffmpeg commands I list above run about real-time,
> that is,
> if I have 30 min input video the two passes complete in about 60 min.
> Athlon XP 2500+.
> I think Mpeg4 is supposed to be slower, right?
>
MPEG4 needs more power for _decoding_ but the encoders are quiet good
optimized (for speed). I think MPEG2 encoders mostly are optized for
quality with nor respect to speed. Even on windows, I only know from
slow (but very good quality) MPEG2 encoders.
> So in the end, either the encoding needs to be made better (adding
> kbit/s doesn't seem to help)
> or postprocessing can be enabled for the result when played.
>
Postprocessing -- in my opinion -- is a way to correct things missed at
encoding time. Take the focus on encoding, as every playback will
benefit from that one encoding.
>> Maybe you could describe your problems and how you fixed them, so that
>> others can benifit of. I did not have much problems installing it, as
>> fas as I remember, but I use mplayer (selfcompiled) for a long time know.
>>
>> Ok, I know, this will not help you to much, but maybe this will help you
>> to explain the problem in more detail to us.
>>
>>
>>
> Well, I
I thought about making a extra post, with a meaningful subject, so that
others will find your hints easy. But what counts is, that you post your
hints.
BTW: Maybe take a look at your Mail- and Replay-Settings. Your mailer is
breaking threads. It seems, you use Netscape 6.1 for mail. As I use
mozilla, I don't understand why this happens at all. Maybe you can find
out, but do not take all your time for it.
I think we get closed to the problem! Hope to hear from you!
--
Patrick Cernko | mailto:errror@errror.de | http://www.errror.de
Quote of the Week: "/vmlinuz does not exist.
Installing from scratch, eh?"
(Debian Kernel Installation)
Attachment:
pgp00003.pgp
Description: PGP signature