B Frames

[mcentee]

As you can tell from the last post and this one I'm new to this GK business.....

I am looking to get a Hardware DVD/DivX player (bear with me on this forum thing), and know that there are differeing chipsets available (ESS, SIGMA and MTK) fromt reading/searching the hardware forum.

I would like to be able to use AutoGK and have noticed on my tests that it produces files that look like this with AVICHeck:

File: D:\video\DVD_Rips\lotr_2\tt_xvid_2ch_ac3.avi
Total Streams: 2
Running Time: 0:03:02
Index Chunk: Yes
Interleaved: Yes
Max Bytes Per Sec: 0
AUDIO: 0 - AC3 (0x2000)
Average Bitrate Per Sec: 255 kb/s
Samples Rate: 48000 Hz
Channels: 2
Bits Per Sample: 0
VIDEO: XVID
B-VOP: Yes
S(GMC)-VOP: No
QuarterPixel: No
Frame Size: 608 x 240
Frames Rate: 25.000
Color Depth: 12
Total Frames: 4574

Elapsed Time 00:00


Now, I know that there are some threads saying that the SIGMA and ESS only support some aspects of DivX/XVid, and I would like to know if the "B_VOP: Yes" line above would mean these files would not play on those machines, or whether the limitations are something else to do with B-Frames ?

I know AutoGK is wonderful and easy and is intended to produce "simple" files.

If this is the case and the files wouldn't be playable then I would be looking to either wait for MTK players in the UK or learn to use the big GK itself and reset B-Frames to "no" somewhere, or is there an option somewhere in AutoGK to do this (ini file or something) ?

Many thanks

[Doom9]

to my knowledge, autogk uses one b-frame so that is supported on all divx capable standalones.
And no, currently there is no way to reconfigure the codec.

[mcentee]

Many thanks - I have run the test clips through AutoGK (DivX 5) with B frames as well as Dr DivX without the B Frames and honestly cant tell much difference at the moment.

AVICheck (by SIGMA) seems very basic as it just says "yes" or "no" next to the B-VOP parameter, not whether it is 1 or 2 etc B Frames, hence the question above.

Is there a better tool for looking at created AVI's and getting more detail on this? I have Gspot but that doesn't say either.

[len0x]

Divx5 b-frames are supported by all standalones indeed, xvid ones are somewhat more tricky. We were reported that for instance YAMADA 6100 has issues with it (and with xvid in general). I believe it's more firmware problems then hardware. So my advice is to do some research about that as well as to look at support for players(i.e. how often firmware upgrade is released by the vendor as it is important indication of how feature-rich your player will be).

[mcentee]

Ok - I was thinking of the Yamada in particular because its easier to get hold of in the UK.

I can understand that it might have problems with multi B-Frames, but are XVid "single" B-Frame streams so different to DivX 5 single B's ?

Just an aside on aspect ratios. With AutoGK it chooses to crop my 2.35:1 clips, and present me with a finished avi at either 640 x 256, or 608 x 240. This gives ARs of 2.5:1 and 2.533, which is dofferent to the original. Is this a "feature" of AutoGK, or GK ingeneral, and is tehre a reason why the 2.35:1 can't be kept ?

Cheers

[len0x]

Originally posted by mcentee
Ok - I was thinking of the Yamada in particular because its easier to get hold of in the UK.


this one doesn't seem to support even latest dev-api-3 builds (summer ones), so I don't think it's a good choice. So it's not only b-frames problems...

If you can't wait until new generation of players is out with mediatek chip - you might want to look at LiteOn LVD 2001. I have it and it does play everything its chip can play... My feeling - XviD is even played better than DivX...

Originally posted by mcentee

Just an aside on aspect ratios. With AutoGK it chooses to crop my 2.35:1 clips, and present me with a finished avi at either 640 x 256, or 608 x 240. This gives ARs of 2.5:1 and 2.533, which is dofferent to the original. Is this a "feature" of AutoGK, or GK ingeneral, and is tehre a reason why the 2.35:1 can't be kept ?


How can you be sure that 2.35:1 ratio is the correct one? (DVD label mean nothing) AutoGK crops black bars and then that ratio is the real one.

[mcentee]

Hmmm..methinks the Yamada is a no-no then. Patience s the hey, but as soon as I go for an MTk (when in the UK) I bet there will be something even bigger and better just around the corner.

Ok - maybe this is a feature of the DivX (Dr Divx) player I am using.

I have used Power DVD to look at (and measure in cm!) the vert x horiz picture size for the original vob and the encoded divx5/XVid clips and they do have the same playback aspect ratio - in this case it is 2.35:1.

(edit: Mind you I still don't understand where AutoGK gets the 2.5:1 ratio's from, and if 2.5:1 *really* is the film ratio why PowerDVD plays it back at 2.35:1)


Thanks again