packed bitstream in .ogm?

[chilledoutuk]

Lately i have been using the .ogm container for my encodes.

Acording to crustys FAQ regarding packed bitstream:

"It's meant to solve frame-order issues when encoding to container formats like avi that can't cope with out-of-order frames."

Can .ogm's cope with out of order frames?
Is there any point in using packed bitstream with the ogm container?

cheers

Regards

ChilledoutUK

[Neo Neko]

Well this would have possibly been better posted to the new container section. But it is a close call as it has a tiny bit of dual relivence. Koepi can probably be a bit more specific with this. The best I can say is that the majority of the advantage to OGM are audio related. But in the end packed bitstream is more for editing convinience and not really related to out of order frames(??) or VFR issues. Because there is no way for AVI to support VFR in any manner. IIRC Divx has chosen packed bitstreams as their default. But you do not need packed bitstreams. Xvid files play back just fine without packed bitstreams. The reason the Xvid group added packed bitstreams IIRC was for added Divx interopperability and to get rid of the bframe decoder lag when editing in aplications like virtualdub. Other than that it serves little purpose. I don't use it because I like more than 1 bframe and all libavcodec based software have problems with more than 1 consecutive bframe in a packed bitstream. Software like Mplayer, VLC, ffmpeg.

[nanoflower]

So is there any disadvantage to using packed bitstreams with alimit of 1 consecutive B frames? From what Neo Neko states it seems that packed bitstreams shouldn't cause a problem (whether used in AVI/MKV/OGM files) so long as the number of consecutive B frames is limited to 1.

[crusty]

Well, IIRC, an ogm is basically an Avi inside a container. The advantage of this is that you can safely use VBR audio formats like vbr mp3 or Ogg vorbis with avi. Ogg Vorbis cannot be used with pure avis, and vbr mp3 is known for possible A/V sync/lag issues (especially with older, improperly muxed avis).

Also, packed bitstream could be an advantage on standalone hardware players, to give XviD avis better compatibility with players that can only decode DivX.
But, I know of no hardware player that can play ogm files. There might a few out there but it renders the use of packed bitstream in ogm's kinda useless.

Remember: XviD decoder will always playback XviD files, no matter if you used packed bitstream or not. So if you just encode for playback on your computer, packed bitstream has no use.

The advantage of packed bitstream is that you might get better DivX compatibility on standalone's (this of course, depends on the model and make of the standalone; there's no such thing as a 'standard' standalone) and that a silly and harmless error message in Virtualdub doesn't show up. Also seeking and cutting is supposed to be better with it but I've never had any problem with that anyway.

The disadvantage is that it might also create playback issues, especially with ffdshow.

To sum up my experience:
I've seen people reporting issues with it.
I can't remember people reporting issues solved with it.
Extra overhead with it is negligible.

As you can see, it's kind of a mixed bag of results.
Therefore, recommended setting is off. If someone disagrees with me, feel free to add.

In any case, I don't use it. :p
HTH

[bond]

Originally posted by crusty
Also, packed bitstream could be an advantage on standalone hardware players, to give XviD avis better compatibility with players that can only decode DivX.
The advantage of packed bitstream is that you might get better DivX compatibility on standalone's (this of course, depends on the model and make of the standalone; there's no such thing as a 'standard' standalone)i wonder where this saying come from?

all players which claim to have xvid support (i dont know anyones which cant do it) can handle it without packed bitstream!
but some (i dont remember whether it was sigma or ess or both) have problems with packed bitstream (when used with 2 or more b-frames as it is default in xvid)

so if you want to be sure that you can play the files on all standalones you definitely should disable packed bitstream in xvid!

[Zhnujm]

Well, my first player (elta 8882 Sigma) could only play xvid with more than 1 bframes if packed bitstream is enabled, my curent player (elta 8883 Mediatek) can only play bframes if packed bitstream is disabled.... :rolleyes:

[bond]

:p

[crusty]

LOL!!

Well I guess that clearly states my point....it's a very mixed bag of results!!

:D

[ChristianHJW]

b-frames in AVI is a hack, started by DivX Networks. What else did you expect to be the outcome of this mess, than an even bigger mess ?

[Alxemi]

my curent player (elta 8883 Mediatek) can only play bframes if packed bitstream is disabled....

Are you sure? My mediatek based Ascomtec 3004 plays XviD 1.0 bframes perfectly with packed bitstream enabled (even 2 or 3 consecutive)... :confused:

didn´t test with packed bitstream disabled, but why should I if enabled works fine :D

Just a joke i will test to post here, maybe mediatek handles bframes with or without packed bitstream, let´s see.

[Zhnujm]

Maybe not more than 1 bframe is used in this files ?
I have also some test files that run perfect even if 2 or 3 bframes are enabled, i think thats because not more than 1 gets used.
Even if i use the Ascomtec firmware theres no difference.

[crusty]

I actually found 1 dvd-player (i think it was a KISS one) that is supposed to handle ogm. So they are out there, but not in the numbers that would really validate ogm for standalone use, imho.

[Alxemi]

I actually found 1 dvd-player (i think it was a KISS one) that is supposed to handle ogm

Hum.. I think you made a mistake with this. There are several players that can handle OGG-Vorbis audio codec, but no one that could do the same with OGM (The multimedia container). There were rumours about that new mediatek based players could do it, but it seems that were hoaxes (till now) :P

And Zhnujm, about the bframes, I´m sure that my encodes has two and even three consecutive bframes and the player handles them well,.. with packed bitstream enabled of course. Without it enabled still untested... I will do it soon

[McGee]

Would packed bitstream prevent the stalled first frame of an .ogm muxed and split with OggMux?

[Koepi]

Packed bitstream has nothing to do with a keyframe (or the lack of one).

Regards
Koepi

[Zhnujm]

@Alxemi:
If you could try this file we would know for sure, it does not run smooth on my player:
ftp://zhnujm.dyndns.org/packet.avi (1.7MB)

[Alxemi]

If you could try this file we would know for sure, it does not run smooth on my player:

Doesn´t run smooth on mine too. It´s the first time it happens in my player Hum... I´m now preparing some tests with several bframes settings. Maybe it is not the bframes configuration or the packed bitstream setting :confused: I´ll post the results in the hardware players forum because we are a little offtopic now :)

[crusty]

Would packed bitstream prevent the stalled first frame of an .ogm muxed and split with OggMux
AFAIK, no.
I believe it's a known issue with splitting not occuring on keyframes.
Packed bitstream won't help you there....

[Alxemi]

Hum.. It seems that i was wrong about the Packed Bitstream setting as you can read here (http://forum.doom9.org/showthread.php?s=&threadid=71554). Sorry for speak so fast :rolleyes:

[crusty]

@Alxemi:
Hum.. I think you made a mistake with this.
You're right I misread Ogg Vorbis for Ogm.
The link is here:
http://www.kiss-technology.com/?p=dp558&v=users

[Alxemi]

So one for another :D