Problem scenes with Sigma 8551 & AGK

[laserfan]

Users of Pinnacle ShowCenter (SC) standalones have struggled with Xvid encodings from Day 1 it seems, and out of the 90 or so AGK movie encodings I've made (a couple hundred hours!), there remain (only) a few short scenes that appear impossible to get to play smoothly. I do of course have the "Sigma compatible" set in Hidden Options, but there are several scenes in particular (grass-cutting and birds flocking in "Winged Migration", and cougar-attacks-bear at the end of "The Bear") which do not play smoothly no matter HOW I try to encode them.

I've been led to believe that the SC/Sigma 8551 struggles with high bitrates (>2500 i think) but even when I take the bitrate down, I still have problems w/these scenes. The only analysis tool I have found to operate on Xvids is DRF Analyzer, and it doesn't give bitrate--I think it is saying for these scenes that FRAME SIZES are very high for a brief period. Heck, I don't even know what this means.

What I am trying to find, is a thread/discussion/forum somewhere which discusses the subject of AGK's hidden option for Sigma standalones, the matrices associated therewith, etc. so I can learn more about this and try to resolve the problem (not just for these scenes, but to reassure myself that my encodes don't have hidden stuttering & jerkiness).

I have eliminated other possible causes (than Sigma/Xvid incompatibility) for the jerkiness such as player or network speed. These scenes play just fine for example if I just play the original VOB files on the SC (with their much higher bitrates of course).

Any thoughts or advice (OTHER THAN "SC is crap!") would be most welcome.

[len0x]

Well if you know for sure that bitrates higher that 2500 are problematic for SC then nothing can be done as DXN HT profile has it capped at 4000. Recompile of xvid sources would be needed to lower that capping. Its easier to switch to DivX in your case...

[laserfan]

>if you know for sure that bitrates higher that 2500 are problematic...

Actually I do *not* know this for sure, I only do know that the SC uses the Sigma EM8551 and that every SC owner using Xvid has struggled with compatibility.

You mention the DXN HT profile len0x and yet when I look at "Configure Encoder" for my Xvid installation there is instead the MTK NTSC profile selected. I have assumed that this selection was made automatically by choosing the MTK/Sigma Standalone option under CTRL-F9.

Should I be trying instead DXN HT?? Sorry for these questions, but there seems very little concrete info anywhere on what "Enable standalone support" intends to do and how it is implemented.

[len0x]

MTK profiles are exactly the same as DXN, but with custom matrixes enabled (which makes no real difference to the bitrate), but you can try setting ESS compatiblity...

[laserfan]

Well, I tried Divx 5.2.1 and it glides-thru the problem scenes w/no trouble at all.

Maybe re: Xvid "compatibility" the real answer is to stop beating my head against that particular wall.

But I remain puzzled why no one here seems to know-or-care whether Xvid works w/Sigma Designs EM8551??? Maybe they're still pissed at Sigma for past indiscretions... :devil:

[len0x]

coz I know of plenty Sigma based standalones that have no problems playing XviD, so it seems to be SC issue only (and then we back to "SC is crap" :) ).

[SeeMoreDigital]

If you are generating XviD encodes with B-VOP(s) you might want to try switching off either the VHQ or AQ implementation.... I can't remember which one the Sigma EM8551 chip-set does not like!

I will try and check this out sometime tomorrow :eek:

EDIT: It should not matter whether you use packed bit-stream or not, or the MP4 container either...

EDIT 2: Here a link to some bit-rate tests (http://forum.doom9.org/showthread.php?p=625252#post625252) I conducted some time ago, with the ADS Media-Link, which is fitted with the same chip-set.


Cheers

[laserfan]

If you are generating XviD encodes with B-VOP(s) you might want to try switching off either the VHQ or AQ implementation.... I can't remember which one the Sigma EM8551 chip-set does not like!...Thanks for your reply SMD. I have as I said been using Dvix successfully for a couple of days, but it seems a.) to not compress as well as Xvid and b.) to look worse in the process (!) so I'm not real happy using it. May be my imagination but I swear the difference is noticeable.

Anyway I have only been using AGK w/defaults & Hidden Opts "sigma standalones" but I will do some nosing around about the above and see what I can find. Funny about yr link; musicnyman was active on the Pinnacle boards w/his ShowCenter but has lately disappeared--I imagine he chucked his unit. I have 3 including the latest SC200 (EM8620) and am generally very happy...

Back to the problem though: one thing is certain: I have the perfect scenes in 'Winged Migration' to stress the encoding!

[laserfan]

I did a few run-thrus on the problem scenes, puzzling over how to change the Xvid settings--while AQ is off, VHQ is On, but if I run AutoGK with Standalone option checked, it appears to over-ride any settings I might have made with the "Configure Encoder" utility of Xvid.

Anyway as I was testing, I noticed my "problem scenes" were not skipping--what the...? After puzzling over this for a few iterations, I realized what was different about these tests--I had set the Audio options in AutoGK to MP3 VBR, and was encoding w/only 1 audio track. I normally encode w/both an AC3 track and an MP3 track (Auto audio mode, two tracks selected in main screen).

My strong suspicion now is that these scenes, coupled w/TWO audio tracks AC3 & MP3, are what is "too much" for the 8551 to handle. But I can't confirm it right now as I've run into another problem--AGK 2.15b and 2.16b seem to be broken in re: getting two audio tracks in 2-pass mode.

I placed a msg in the 2.16b thread and am calling it a night for now...

[SeeMoreDigital]

Thanks for your reply SMD. I have as I said been using Dvix successfully for a couple of days, but it seems a.) to not compress as well as Xvid and b.) to look worse in the process (!) so I'm not real happy using it. May be my imagination but I swear the difference is noticeable.I forgot to mention... when you use XviD with DivX profiles you still have the option of being able to select AQ and or VHQ....

Does anybody know whether DivX uses AQ or VHQ (or something similar) with B-VOP(s)?

Anyway, I found some of the (video only) XviD 2B-VOP test samples I used... Why not give them a go with the ShowCenter: -

XviD 2B-VOP with PBS (http://homepage.ntlworld.com/seemoredigital/MPEG-4_Player_Test_Files/XviD_2B-VOP_with_PBS.7z)

XviD 2B-VOP without PBS (http://homepage.ntlworld.com/seemoredigital/MPEG-4_Player_Test_Files/XviD_2B-VOP_without_PBS.7z)

Each folder contains 4No samples, with variations of AQ and VHQ.


Cheers

[laserfan]

Hmmm SMD, as I said, when I used "Configure Encoder" to turn-off "VHQ for b-frames", then ran AGK, then went-back to look at the Encoder settings again, they had all been reset, so I assume AGK is over-riding my Encoder changes.

What might I be doing wrong here.

Thanks I've dl'ed yr files and will give them a go, gotta find something that unzips 7z files as WinRAR doesn't seem to work.

[SeeMoreDigital]

Hmmm SMD, as I said, when I used "Configure Encoder" to turn-off "VHQ for b-frames", then ran AGK, then went-back to look at the Encoder settings again, they had all been reset, so I assume AGK is over-riding my Encoder changes.I fired up my ADS Media-Link earlier today and fed it with some XviD B-VOP encodes in .AVI.... And in my case it's XviD's VHQ option my device does not like. Plus, it gets worse without packed bit-stream!

Thanks I've dl'ed yr files and will give them a go, gotta find something that unzips 7z files as WinRAR doesn't seem to work.Look in my "sig" :)


Cheers

[laserfan]

SMD am I doing this right? Why, when I set Xvid properties directly using its Config Encoder, do those settings revert after I've used AGK?

It certainly appears to me that AGK is over-riding me? Please advise.

[SeeMoreDigital]

Sorry I can't help you with AGK settings.... I don't encode with it....


Cheers

[len0x]

you can't override XviD settings in autogk

P.S. I can't possibly imagine how VHQ can influence ouput stream in terms of mpeg4 compliance. Its like discover that phycho enhacements in DivX would make stream play jerky... May be its pure coincindental that VHQ influences bitrate spikes in a bad way...

[laserfan]

you can't override XviD settings in autogk...Thanks len0x I thought this was the case. SMD I appreciate your help but note the subject!!?? What is your preferred tool instead.

As I said above I do think now that this is probably not an Xvid issue at all, but something to do w/2 audio tracks instead. I will post here again when I reach a confusion, er conclusion!

[SeeMoreDigital]

SMD I appreciate your help but note the subject!!?? Errrrrm... Is not the underlying purpose of your thread to determine the cause of your problem!

Please try the encodes I provided with your device. And if you find you can play some of the files but not others, then you'll be in a better place than you are now ;)

What is your preferred tool instead.MPEG Mediator and VirtualDubMod

As I said above I do think now that this is probably not an Xvid issue at all, but something to do w/2 audio tracks instead. I will post here again when I reach a confusion, er conclusion! Yep.... incompatible audio and video muxing can often be the case of peoples problems.... Which is why I've found it's always good policy to test devices with "video only" samples too.


Cheers

[len0x]

FYI - ESS option in AutoGK actually forces different audio muxing settings, so you might try that as well...

[laserfan]

Thank you, guys, but I do now have enough testing under my belt to assert a couple of "final realizations" about this:

1. The trouble that myself and probably other ShowCenter (EM8551) users have had with skipping & stuttering w/some XviD encodes lies not solely with XviD by itself, but rather with the combination of XviD and AC3 and MP3 (dual audio track) programs.

Early versions of the ShowCenter product did not include Downmixing of DD tracks to the SC's analog outputs, so if we intended an SC to be used with an analog audio system (e.g. ordinary TV w/stereo inputs), we were compelled to encode w/MP3 audio. Since we also wanted AC3 for other players or for the future, we encoded with both audios, and the SC allows for switching between the tracks. I always encoded this way, and used VDubMod to re-stream the audios so that the MP3 track was 1st, and the AC3 track was the 2nd audio stream.

2. The same programs (using XviD, AC3, and MP3 in combination) that skipped in certain complex scenes (some good ones for testing in Winged Migration & The Bear -- those French seem to know how to make 'em!) when stripped of their MP3 tracks DO NOT SKIP ANYMORE. Since AC3s tend to be 384kbps and MP3s only 128kbps I assume that the problem is still not really w/bitrate, but rather with the way these streams are interleaved and the way the 8551 wants to decode them.

3. A caveat to the above is that if I use DivX 5.2.1 for the video encode, and again keep 2 audio tracks AC3 and MP3, these problem scenes do not skip. So again there seems to be something unique about the Xvid/AC3/MP3 combo that is troublesome here.

3a. As a side note, I observe that encoding with DivX 5.2.1 positively SUX by comparison to even much lower bitrate XviD encodings. I've never used Divx before but must say as a relative novice to these codecs that I am surprised, for a <somewhat> commercial product, just how bad at least v5 is in comparison to Xvid. Kudos to the Xvid developers, whoever you are!!! Incredible stuff!!!

4. There may yet be a solution somewhere to this, i.e. maybe there's a setting for converting to MP3 that would help, or some repairs that could be invoked using VDubMod, but I don't feel adequate to this task, nor do I find it something that I need to try to do, because I have decided instead to stop recording two audios, and instead use the new ShowCenter ability to downmix AC3 tracks to analog-output. I intend therefore to encode w/AC3 only from now forward, and for those encodings I have already made, I can use VDubMod to re-stream them without the MP3 stream. I'm confident that if there was any "hidden skipping" in my encodes (I have not looked at all 200+ hours of them!) that this process will eventually clean them-up such that I won't have to worry about them anymore.

Thanks again for all y'all's help SMD and len0x. I hope this discussion has helped others as it has helped me!

[SeeMoreDigital]

Hi laserfan,

I would still be most grateful if you could play my samples with the ShowCenter please. I am particularly interested to know whether the "VHQ" samples cause problems for you too!

I must admit one of it's weaknesses of the ADS Media-Link is its inability to select between audio tracks... Plus it's utterly awful remote control :eek:


Cheers

[laserfan]

SMD I have your samples already--will grab 7zip and check them out later today!

[laserfan]

Well, SMD I'm sorry to say that I don't know that I am going to be able to help you. Your files DL'ed and unpacked just fine, and in fact they imported to the Pinnacle MediaManager (server) software OK (not rejected), but they also appear with a (!) mark next to them, and as such aren't available as selections from my 1000 boxes. I dunno what to make of this yet, maybe the 25fps files aren't playable on an NTSC system?

I have an SC200 here also--I'll fire THAT up later and see if IT "sees" these files, not that it helps in re: our 8551 questions...

EDIT: It occurs to me that there is supposedly a new feature in the Pinnacle software that would allow my sc1000 to "see" directly files-in-folders. Maybe I can bypass the server software in that way, and try to play the files directly. More to come...

[SeeMoreDigital]

Bummer.... That's a first (for me)....

Thanks for giving it a go.... I'll have find and harass a PAL ShowCenter user. Which will be a pain because most of the people I knew with them, have sent them back :eek:


Cheers

[laserfan]

SMD, thanks to Pinnacle's new direct File Access feature, I was able to bypass their MediaManager app and play your files directly from my SC1000 wired. Note all files played glitch-free on my PC. Unfortunately NONE of them played glitch-free on my SC1000.

First, I set the 1000 to 4:3 Letterbox mode which was the only way to achieve proper AR (looks like 2.35:1).

The glitches I saw were in the bottom fourth to bottom third of the frame (not the bottom of my 4:3 NTSC TV, but the bottom of the encoded video, above the black letterbox). I do not know how to properly describe these "glitches"--the best I can say is that there was "breakup", not pixelation or stuttering that I am familiar with, but a very quick, double-pulse breakup, but only in the lower portion of the picture (the upper part of the frames seemed at all times to be perfect). Another commonality is that the breakups occur always at the very beginning of a new scene; also scene 3 breakup seemed in most cases to be the worst.

The least glitchy of the files were the +AQ-VHQ ones, and these were very noticeably better than the rest, whether +PBS or -PBS (what's PBS?). In no cases would I say the breakups were acceptable--it would not be possible to watch a 2 hour movie with these (as I'm sure you know & agree!).

Anyway, my feedback may be meaningless because I dunno if an NTSC-switched ShowCenter, and NTSC analog TV, like these 25fps clips or not! But there you are.

Now I wanna go-out and buy the movie! :p

[laserfan]

SMD for grins I played your files on the new SC200 (EM8620) tonight and they all played completely glitch-free from start-to-finish. My setup of course is NTSC, component 720p from SC200 to 60" HDTV.

Before, on my interlaced set w/SC1000, I had thought that the cuts from scene-to-scene appeared "twitchy" (I mean apart from the glitches I reported already) and my feeling was confirmed by the total LACK of jumpiness or artifacts of any sort w/the progressive setup.

I guess I'm just a little surprised your files play here but then again I'm no TV engineer...

[laserfan]

Having now done now quite a lot of testing wrt playback problems, it is my humble belief that apart from just high bitrates that the ShowCenter box clearly can't handle, that it also has difficulty with the VBR MP3 files that AGK forces when you select both the original AC-3 track and an alternate (same, but MP3) audio track. I believe this because I've done other encodings now with a different tool, at similar total bitrates, but instead with a CBR MP3 track instead of VBR MP3. No problems it seems when both audios are CBR (AC3 & MP3).

Getting the different tool's settings to be identical to AGK's is not easy of course, maybe not even possible, so it's difficult to state with authority that VBR is ABSOLUTELY the problem. In any case, since the SC system no longer requires these two identical-but-different audio tracks anyway, I'm not going to do this anymore and my quest is ended. I'll encode only a single AC3 track from now forward. This reminds me of an old joke:

Patient: Doctor, it hurts when I do that!

Doctor: Well then DON'T DO THAT!