Re: [Encode2mpeg-users] encoding for the Philips DVP642

[Giacomo C. <enc...@us...>]

On Fri, Oct 28, 2005 at 09:35:07PM -0700, Adam Monsen wrote:
> I did quite a few tests, so I thought I'd share some of my results. First,
> the bad news, I wasn't able to solve the choppy video and audio sync issues.
> 
> encode2mpeg -o 312bframes in.avi -avionly -encode 3:1:2 -ffourcc DIVX
> -setaspect 6 -turbo 1 -bframes 2
> 
> 312bframes.avi turned out to be 1553.4 kbps, 689.7 MB, and took 2h17m44s to
> encode. For some reason, this file wouldn't play on my Philips DVP642
> standalone DVD player.
> 
> encode2mpeg -o 332 in.avi -avionly -encode 3:3:2 -ffourcc DIVX -setaspect 6
> -turbo 1
> 
> 332.avi turned out to be 1285.3 kbps, 581.8 MB, and took 4h5m49s to encode.
> The quality was great but playback slowed during complex scenes and the
> audio still fell out of sync (after 10min or so of playback).
> 
> encode2mpeg -o 742 in.avi -avionly -encode 7:4:2 -ffourcc DIVX -turbo 1
> -setaspect 6
> 
> 742.avi turned out to be 2367.7 kbps, 1.1G, and took 5h3m11s to encode.
> Quality seemed better than 332.avi, but the same problems existed (choppy
> playback and audio that fell out of sync).
> 
> I doubt this is a problem with encode2mpeg, I'm sure the DVP642 is just
> picky about what will play well.
> 
> Since I have a few other videos encoded with Nandub and VirtualDub that seem
> to play well, I'm now going to try to create videos exactly like those with
> encode2mpeg and see if they'll play well on the DVP642.
> 
> Here is some select information from mplayer playback of a video
> that *does not* play well on the Philips DVP642.
> 
> --- video I made (choppy playback, audio falls out of sync) --
> VIDEO: [DIVX] 640x480 24bpp 24.000 fps 1285.3 kbps
> Software: MEncoder 1.0pre7-4.0.0
> AUDIO: 48000 Hz, 2 ch, s16le, 40.0 kbit/2.60% (ratio: 5000->192000)
> Selected audio codec: [mp3] afm:mp3lib (mp3lib MPEG layer-2, layer-3)
> 
> Here is some select information from mplayer playback of a few videos
> that *do* play well on the Philips DVP642.
> 
> --- sample video that plays well on the DVP642 ---
> VIDEO: [XVID] 576x304 12bpp 23.976 fps 733.8 kbps (89.6 kbyte/s)
> Software: Nandub v1.0rc2
> AUDIO: 48000 Hz, 2 ch, s16le, 448.0 kbit/29.17% (ratio: 56000->192000)
> Selected audio codec: [a52] afm:liba52 (AC3-liba52)
> 
> --- another sample video that plays well on the DVP642 ---
> VIDEO: [XVID] 608x256 12bpp 23.976 fps 828.8 kbps (101.2 kbyte/s)
> Software: VirtualDubMod 1.5.10.1 <http://1.5.10.1> (build 2439/release)
> AUDIO: 48000 Hz, 2 ch, s16le, 128.0 kbit/8.33% (ratio: 16000->192000)
> Selected audio codec: [mp3] afm:mp3lib (mp3lib MPEG layer-2, layer-3)
> 
> * The videos that play well are all 12bpp, but mine is 24bpp. Maybe this
> makes a difference. Is there a way to reduce the color depth of encoded
> video to 12bpp with encode2mpeg?
> 
> * The videos that play well have smaller dimensions than the one I made.
> Might that make a difference, too? I could try reducing the size.

I do not have a simple answer to your doubts. For the moment I'm busy
working on the next relase of encode2mpeg. It should be ready in about
two weeks. After the next relase I will concentrate on DivX Mode and
find a way to make your player work.

I have a question. The a/v desync appears always after about 10 minutes?
It is related to the choppy video?
Once the desync appears, it stays always there or at some point
it disappears? And if it stays, the delay is constant or increase with
the time?
I also assume that the desync and choppy video do not appear if you use
mplayer to play the avi, isn't it?

In the mean time I can only ask you to test some other encoding combination
in order to see if we can track down the problems to a specific audio codec.

For the tests I suggest to use -encode n:1:1 or -encode n:2:1 (if the previous
do not work). They are faster and for the tests you are doing now 
speed may be important for you.
Check if the a/v desync appears with mp2, ac3, mp3 cbr.
Use -encode 4:m:i -encode 6:m:i -encode 5:m:i
Do not use -fixasync for this test.

Another thing. You do not need to use the option -turbo. 
encode2mpeg will use turbo automatically when necessary.

Giacomo

> 
> On 10/24/05, Giacomo Comes <enc...@us...> wrote:
> [...]
> 
> > > (1) when there is a lot of movement, the
> > > video gets choppy, and (2) the audio gradually slows down compared to
> > the
> > > video. Any ideas of options I might add to make this video a bit more
> > > playable on this particular standalone player? The spec sheet mentions
> > that
> > > GMC and Q-Pel are not supported, but I don't think mencoder enables
> > these by
> > > default, so this shouldn't be a problem. Video encoded with
> > > Nandub/VirtualDubMod (Windows) seems to play perfectly.
> >
> > For problem (2) you should add the option -fixasync. Please try it
> > and tell me if this elimitane the the a/v desync when you play it
> > with your player.
> > For problem (1) the solution should be to reduce the video bitrate.
> > During fast motion scenes, the encoder need to use a higher bit rate
> > in order to preserve the quality. This is not a problem with a software
> > player where the data transfer rate from the harddisk or DVD drive is big.
> >
> > But a hardware DVD player is more limited and the peak data rate can be a
> > problem.
> > You have different options in order to reduce the bit rate:
> > 1) Add bframes. Use the options -bframes 2
> > or
> > 2) Use a better compression option: -encode 3:3:2 (with this option
> > bframes are used automatically, add -bframes 0 to turn them off).
> > or
> > 3) Decrease the video bit rate: use -usesbr or -vbitrate
> >
> > You can try to find the maximum data transfer rate of your player.
> > Do diffenrent encoding with different argument values of -vbitrate
> > and check the high motion scene. Do a binary search until you find
> > the maximum video bit rate that do not produce choppy video.
> > (in order to be reliable you should also use a cbr audio encoding)
> >
> [...]
> 
> --
> Adam Monsen
> http://adammonsen.com/blog/

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