Xcard on 3.11 codec [Archive]

anGGa

1st May 2002, 12:43

Hey,

I've been waiting long for this card to come out and couldnt wait to buy it. But since I read some of the specs, I doubt that ill be buying this card unless it will play movies encoded with the 3.11a codec.

What's the point of buying a card that cant play 3.11 movies? I mean...all the best HQ movies are released by Groups and they only use the 3.11a codec.

So it wouldnt be possible to play the best quality for a movie using the Xcard.
All we can do is play movies released by a
non-group, which is not the best quality u can get. Im not sayin that there arent any HQ movies released by non-groups or encoded with codecs different than 3.11a, its just not the best. Thats all.

I just hope there will be a way to play 3.11a movies using this card so I can buy it....but till then It'll be just standard monitor-watching for me ;)

-h

1st May 2002, 12:59

Well I assume the "Xcard" is a hardware MPEG4 playback device, and seeing as MSMPEG4V3 isn't MPEG4 spec-compatible, it's not going to work too well.

There will eventually be a program to convert your 3.11 movies to "standard" MPEG4 streams, however I'm not sure how far from release it is...

-h

anGGa

1st May 2002, 13:57

Well actually I dont want to convert my 3.11 movies, I just want a card that is compatible with all the codecs :D

-h

1st May 2002, 14:39

Well actually I dont want to convert my 3.11 movies, I just want a card that is compatible with all the codecs :D

Such a card will never exist. Sorry :)

By conversion, I meant that it's lossless (i.e. a straight conversion of the bitstream, no re-encoding).

-h

anGGa

1st May 2002, 14:45

Originally posted by -h
[i]

By conversion, I meant that it's lossless (i.e. a straight conversion of the bitstream, no re-encoding).

-h

That would be nice; no re-encoding...

wing1

1st May 2002, 22:33

quite interesting....3.11a is not supported. If this is the case, then 3.11a will suffers the same issue when MPEG4 enabled DVD players are release would it not? When this happened, will the "release group" convert their products over and use the "non-group" method :D ?

avih

1st May 2002, 23:13

-h

2nd May 2002, 00:31

if a tool to convert 3.11a stream to mpeg4 will exist (and i agree with -h it's possible), then there should be no problem doing it 'on the fly' just like the 800M filter convert raw mode2 form 2 files to 'clean' streams. when this happens, i guess you'll start seeing players that support playback of divx3.11 on xcard. (initially for computer, and possibly stand alone players after them)

I assume the card isn't decoding the bitstream itself, it just requests an array of macroblocks (along with flags such as not-coded, etc.) and then performs the dequant/iDCT/compensation in hardware.

In such a case, all you'd need is the API for the card itself, since the only real differences between MPEG4 and MSMPEG4V3 (that I've noticed) are bitstream-related. Once you have that array of coefficients, it's all the same, and a player could send any arbitrary array of coefficients as long as it was H.263/MPEG4 compliant quantization. You could probably decode MPEG2 with this thing too..

I'm sure ffmpeg could be adapted to perform a full bitstream conversion right now. All the code's there, you just need to skip some bits.

-h

anGGa

2nd May 2002, 00:53

I guess since im going to have wait some more to have a card that plays 3.11, i just change my mind and buy a card with tv-out instead. That way basiclly i can play everything, right?
Any suggestions which card I can buy?

temporance

2nd May 2002, 01:20

-h:

Are you sure that a 3.11 to MPEG-4 converter is possible? I thought about this project but concluded that enough things were different to make a lossless translation impossible (e.g. method of quantisation).

I'd be interested in a project to do this - if it is indeed possible.

-h

2nd May 2002, 02:53

Are you sure that a 3.11 to MPEG-4 converter is possible? I thought about this project but concluded that enough things were different to make a lossless translation impossible (e.g. method of quantisation).

From a quick look (ffmpeg's msmpeg4.c) the only differences are in things like MV storage, VLC tables, AC/DC prediction, etc. so it's all bitstream related. Quantization looks the same (mpegvideo.c), just basic H.263. Thus, as soon as we have our matrix and vectors to be sent to dequant/compensation/idct, we can apply MPEG4 dc behaviour and ac/mv prediction then write everything to an MPEG4 bitstream.

If I had some spare time I'd give it a try :)

BTW the resulting bitstream will be larger than the original MSMPEG4V3 bitstream, since normal MPEG4 has fewer VLC tables and of course the original bitstream had been tweaked for MSMPEG4V3's MV storage / bitstream behaviour. It could add up to a couple percent, when you take into account MPEG4's larger VOL/VOP headers too.

-h

jokklas

8th May 2002, 19:50

Well.. if this can be done nicely later on and then produce, let's say 10% bigger files then the 800Mb CDs that has been discussed will come in handy indeed. Would mean all good 3.11 SBC release could be converted, burnt on 800Mb CDs and then put into a standalone DVD/DivX player =) =) =) =)

mikemikez

8th July 2002, 13:18

Who cares about the few percent, I wouldn't even really care if it wasn't completely lossless. Just imagine how many people have many gigabytes af divx3.11 stuff they would like to play on the upcomming MPEG4 set-top machine!

By that time I will be stuffing all my converted video on writable DVD's anyway which will dratically cut the amount of silver in my drawers..:)

Mike

NeVeRLiFt

8th July 2002, 22:43

Maybe some day XviD will have the Quality of Nandub or Fairuse....
Maybe then the Groups will use it ;)
I will keep using Nandub to encode my DVD rips and using TV-out to watch them!

anGGa

11th July 2002, 08:55

Originally posted by NeVeRLiFt
Maybe some day XviD will have the Quality of Nandub or Fairuse....
Maybe then the Groups will use it ;)
I will keep using Nandub to encode my DVD rips and using TV-out to watch them!

Its already done, just wait for it to go "offcial" if u dont believe me ;) Try looking good to some major grps for their Dir, avi naming :D

mikemikez

14th July 2002, 04:05

Well,

Don't you guys agree that having a DivX 3.11:) to MPEG4 conversion app would be Priority Nr. 1?

I mean. I definately want to be able to play all my old divx3.11 stuff on a set top machine. I even have lots of personal stuff in divx3.11 to which I don't have any source tapes any more...

Mike

western shinma

14th July 2002, 07:08

I'm afraid there won't be much demand for this utility until mpeg4 standalones are widely available. While it might be nice to burn everything in mpeg4 format now so you don't have to burn things over later, consider that playing mp4 files right now is not all that convenient for everyone, and also that the flexibility of these unreleased standalones is unknown. It might not be possible to play files at any given resolution for example, and who knows if VBR MP3 will work (if mp3 is supported at all), or if they will play mp4 files on mode 2 form 2 cds.