XVID conversions too small

[jagabo]

Between 3 - 4 is OK. However, on my Samsung standalone, sometimes it stutters when I use CQ mode.
I can encode it in 2-pass mode, using the same bitrate derived from the CQ mode and it plays normally.
Not sure why, but I think the CQ creates a slightly bigger bitrate spike on high-demand area's.

I told you why -- there is no max bitrate limit when you use CQ mode. When you use 2-pass VBR mode xvid obeys the bitrate limit for the profile you chose.

So in CQ mode if a short sequence requires 20,000 kbps it will get it, even if the final average bitrate is 1000 kbps. In 2-pass VBR mode that sequence will be reduced to whatever the max bitrate for that profile is (for example ~4500 in the Home profile).

This is where Divx has an advantage of Xvid. It obeys the profile's max bitrate even in CQ mode. So if the bitrate is going to be too high at the request quantizer, it will automatically increase the quantizer for that segment to keep the bitrate down.

If you want to see what the bitrate limit of your Samsung player is, encode a series of videos at CBR, 1000 kbps, 2000 kbps, 3000 kbps... then play each one until you see which fails. Keep in mind the player has to read the audio track too.

[coyote2]

959-1190 kbps? That must be average, not peak.

Right. Can you please suggest a program which will report a file's peak bitrate?

If the peaks are also relatively low, perhaps I'll be OK.

[jagabo]

Can you suggest a program I can use to report a file's peak bitrate, please?

I already told you that too: Bitrate Viewer.

Another source of problems for many players is the use of Xvid's 3 warp point GMC. No player I know of outside of a computer can handle that. Many players can now handle Divx's single warp point GMC (including the Philips 5992).

[davexnet]

https://www.videohelp.com/tools/Bitrate-Viewer-2

I get the feeling this thread is starting to go around in circles ...

[coyote2]

Can you suggest a program I can use to report a file's peak bitrate, please?

I already told you that too: Bitrate Viewer.

Sorry everyone. I can't thank you all enough. It was foolish of a noob like me to tackle a project like this.

[davexnet]

Can you suggest a program I can use to report a file's peak bitrate, please?

I already told you that too: Bitrate Viewer.

Sorry everyone. I can't thank you all enough. It was foolish of a noob like me to tackle a project like this.

Not really. Just ask more relevant questions if there is something you do not understand.

[coyote2]

Between 3 - 4 is OK. However, on my Samsung standalone, sometimes it stutters when I use CQ mode.

My old Samsung died, so...

davexnet, I have another big favor to ask, if it would be easy enough, I'd love it if you could please see if your Samsung stutters on the highest bitrate peak of an avi or two:

http://www.yousendit.com/download/T2dmMWZKY3l3TGdpR01UQw
28MB
has a bitrate peak of 6080 @1 minute 15 seconds

http://www.megaupload.com/?d=CF3ZUTKD
481MB
has a bitrate peak of 5712 @49 minutes 09 seconds

I apologize in advance if asking this is rude or demanding.

[jagabo]

Just FYI: I have a five year old old Philips 5960 DVD player with Divx/Xvid support. It had no problems with the peaks in those files when playing from a USB thumb drive.

[coyote2]

http://www.yousendit.com/download/T2dmMWZKY3l3TGdpR01UQw
28MB
has a bitrate peak of 6080 @1 minute 15 seconds

now I've also placed a copy of that file at http://www.megaupload.com/?d=RLT9KK34

(my apologies to anyone who had trouble with the yousendit link)

[davexnet]

coyote2,
I recorded the files onto a DVD re-writable and they play without problems.
They are very short bit-rate spikes; perhaps it's their brevity that allows them to play.

[coyote2]

I recorded the files onto a DVD re-writable and they play without problems.

Sweet, thank you very much, davexnet!

Thank you also to jagabo for testing them on your Philips 5960!

They are very short bit-rate spikes; perhaps it's their brevity that allows them to play.

[coyote2]

The default Xvid settings are reasonable. On the Frame tab you might change the Max b-frames to 1 and select Closed GOP and Packed Bitstream for better Divx compatibility. On the Quantizer tab the MPEG Matrix will be slightly sharper than h.263. But it will also raise the bitrate a bit.

Thank you very much, jagabo, for this very helpful advice on Xvid settings in AviDemux.

Would you recommend any changes to the default Xvid settings in VirtualDub? (I went looking in VirtualDub for the custom settings you suggested above for AviDemux, and I do see these similar ones:

"Quantization type:" [alternatives include "MPEG" and "MPEG-Custom"]
"Max consecutive B-VOPs:")

[davexnet]

There was an encoding guide floating around here recently, it gave the xvid settings used by the "scene",
I set it up myself, got into Regedit and saved the key, so I could restore it as necessary.

It made pretty nice encodes, as I remember.

[coyote2]

There was an encoding guide floating around here recently, it gave the xvid settings used by the "scene"

I'd love to see this, but searches are failing me.

[jagabo]

The "scene" is a bunch of morons stuck in the VCD era where all encodings had to be 700 MB to fit on a VCD. That has little to do with quality.

[coyote2]

The "scene" is a bunch of morons stuck in the VCD era where all encodings had to be 700 MB to fit on a VCD. That has little to do with quality.

Never mind, then!

Any advice on Xvid configuration in VirtualDub, please, jagabo?

[jagabo]

Xvid configuration in VirtualDub is the same as in AviDemux. I usually start with Load Defaults then change:

Profile@Level: unrestricted
Target Quantizer: 3 (higher or lower if I want lower or higher quality)
Max Consecutive V-BOP: 1 or 2 (1 for max Divx compatibility)
Quantization type: MPEG or h.263 (MPEG sharper higher bitrate, h.264 softer lower bitrate)
Packed Bitstream: enabled
Aspect ratio: as required by the particular video
Chroma Optimizer: enabled
Greyscale: according to source
Cartoon Mode: according to source
Quality Preset: User Defined, as follows:
Motion Search Precision: 6 - Ultra High
VHQ Mode: 4 - Wide Search
VHQ Metric: 1 - PSNR-HVS-M
Use VHQ for bframes too: enabled
Use Chroma Motion: enabled
Turbo: enabled
Maximum I-frame Interval: 100 (to make seeking easier during playback)

There are custom matrices you can use but most of the are aimed at unusually high or low bitrates.

http://forum.doom9.org/showthread.php?t=120492

[davexnet]

Yes - don't worry about what the "scene" recommends. I just looked through them again, they're similar to Jagabo's.
They did not touch the max I-frame interval, they left it at 300. They also recommended adaptive quantization.

I was interested in the settings initially because I was more concerned with compatibility with my standalone.
In the end, I somewhat abandoned them and switched to Divx version 6.85. The reason being it was faster,
and for the Divx subtitle support.

[jagabo]

They did not touch the max I-frame interval, they left it at 300.

I use 100 just to make seeking at playback a little easier/faster. Using 100 instead of 300 increases the file size by about half a percent when using target quantizer encoding, depending on the material.

They also recommended adaptive quantization.

Ah, forgot that one. I used to use it. Lately I've decided it adds too many DCT ringing artifacts. But I don't really use Xvid any more. Now I encode with x264 most of the time.

[coyote2]

Xvid configuration in VirtualDub is the same as in AviDemux.

Thank you very much, jagabo, for the settings recommendations quoted below my screenshot. But your mention of Xvid configuration being the same in VirtualDub as in AviDemux perplexes me, since they look very different to me:



In this screenshot, AviDemux is on top, VirtualDub is on bottom. I must be missing something, sorry!

I usually start with Load Defaults then change:

Profile@Level: unrestricted
Target Quantizer: 3 (higher or lower if I want lower or higher quality)
Max Consecutive V-BOP: 1 or 2 (1 for max Divx compatibility)
Quantization type: MPEG or h.263 (MPEG sharper higher bitrate, h.264 softer lower bitrate)
Packed Bitstream: enabled
Aspect ratio: as required by the particular video
Chroma Optimizer: enabled
Greyscale: according to source
Cartoon Mode: according to source
Quality Preset: User Defined, as follows:
Motion Search Precision: 6 - Ultra High
VHQ Mode: 4 - Wide Search
VHQ Metric: 1 - PSNR-HVS-M
Use VHQ for bframes too: enabled
Use Chroma Motion: enabled
Turbo: enabled
Maximum I-frame Interval: 100 (to make seeking easier during playback)

There are custom matrices you can use but most of the are aimed at unusually high or low bitrates.

http://forum.doom9.org/showthread.php?t=120492

[jagabo]

In this screenshot, AviDemux is on top, VirtualDub is on bottom. I must be missing something, sorry!

The organization is different but they have all the same settings. Sometimes with slightly different names. You just have to work your way through all the tabs and buttons.

[coyote2]

Xvid configuration...

Thank you very much again, jagabo, for all this help. Just two more questions please:

Aspect ratio: as required by the particular video

This one has me confused. I hadn't planned to Resize either of my sources (and while I think I get that that isn't what is going on here, I can't wrap my head around what to do either). Both sources are 25fps; the .m4v is 4:3 and the .avi is 352x288

Can you suggest what I should do here, please? (And..."Pixel" or "Display" Aspect Ratio?)

Greyscale: according to source

Am I correct in thinking that, since none of my sources are black&white, it would be good not to enable "Greyscale encoding"?

[jagabo]

the .m4v is 4:3 and the .avi is 352x288

The pixel aspect ratio is 4:3 PAL (both are half the usual 704x576). Or you could just set the display aspect ratio to 4:3.

Greyscale: according to source

Am I correct in thinking that, since none of my sources are black&white, it would be good not to enable "Greyscale encoding"?

That is correct. If you set the Greyscale option the video will become b/w.

[coyote2]

the .m4v is 4:3 and the .avi is 352x288

The pixel aspect ratio is 4:3 PAL (both are half the usual 704x576). Or you could just set the display aspect ratio to 4:3.

Oh, GSpot tells me that 352x288 is 11:9
Should I really pick "4:3 PAL"?
(I can't see how to enter "11:9" into Pixel Aspect Ratio, but I wonder if I should enter 11 x 9 into Display Aspect Ratio?)

I promise these questions won't go on forever!

[jagabo]

Pixel aspect ratio is the aspect ratio of individual pixels (width of pixel : height of pixel). Display aspect ratio is the aspect ratio of the final picture. Without seeing a shot of the video with an object of known aspect ratio (like the wheel of a car viewed directly from the side) it's impossible to say for sure what the proper display aspect ratio of the video should be. But given the dimensions 352x288 it sounds like the video is quarter D1 PAL. That normally has a pixel aspect ratio of 12:11 (pixels are a little wider than they are tall) and a display aspect ratio of 4:3.

DAR = PAR * SAR

DAR = display aspect ratio, the final shape of the picture
PAR = pixel aspect ratio, the shape of individual pixels
SAR = storage aspect ratio, the frame size

DAR = 12:11 * 352:288
DAR = 12/11 * 352/288
DAR = 1.0909 * 1.2222
DAR = 1.3333 --> 4:3

GSpot is telling you there is no aspect ratio information in the file. So it's assuming the video is square pixel where the final display aspect ratio is the same as the frame size aspect ratio. Square pixel means individual pixels have a 1:1 PAR:

DAR = PAR * SAR
DAR = 1:1 * 352:288
DAR = 1 * 1.2222
DAR = 1.2222

In all likelihood, someone took a PAL VCD video (frame size 352x288), or a 704x576 (full D1) video and reduced the dimensions by half, and incorrectly encoded as if it was square pixel. But it's possible the video really is square pixel, maybe from a webcam or something.

[coyote2]

Thank you very much, jagabo, for taking the time to enable me to understand that.

I see now I needn't have asked for a follow-up of your initial answer, and I apologize.

[coyote2]

The organization is different but they have all the same settings. Sometimes with slightly different names. You just have to work your way through all the tabs and buttons.

The only one of the Xvid configuration AviDemux settings jagabo helpfully recommended which I haven't found in VirtualDub is:

with AviDemux...select Closed GOP

My only guess is that...perhaps inputting numbers on this VirtualDub screen



will do it?

[jagabo]

I think the VFW Xvid encoder always uses closed GOPs. There's no way to change it, as far as I know.