VCD problem with Tanky (waitec)

[redout]

I've had the same problem...........
I've burned about 20 cds tring every different setting conceivable with tmpgenc using versions fron a to j.......
No success!
The problem rises only with divx or dvd rips movies, while with movies captured with my "cougar Video edition", or that nice porn clips u can find on the net, i never had any problem.
I've read on the tmpgenc forum something about "evil" B frames, since seems that if u use a gop without B frames the movie plays smoothly (never tried this).
This theory doesn't however explain why with some video sources tmpeg works while with others doesn't.
I temporarly gave up, and now i encode everything with the Panasonic encoder.
I like it because it's quick and dirt, and WORKS, but lacks completely of controls, filters and settings u can find in tmpgenc.
So if anyboy has a final solution i'll be grateful to him for the rest of my life.........
Hope to hear some answer soon.
Thanx

[AntnyMD]

I also suspect the "B" frames issue (in the GOP) to be the issue with Napa DAV players also. In addition to the TMPGEnc VCD template's bitrate set at the maximum allowed in the VCD spec, the number of "B" frames in the GOP is set at the maximum allowed also.

Try lowering the number of B pictures to 4 or less (so that your GOP is about 12-15 pictures or less total per second), and setting your constant/controlled bitrate to 1123, or even 1100. For MPEG-1 video, always tick off Detect Scene Changes, but if you use TSCV or VideoPack 4 for chapters, always tick on the close GOP option (it inserts a sequence header which is necessary for entrypoints).

moments later:
I just took a look at the web site containing this "Tanky." It's a Napa DAV player with a new name.

<font size=-1>[ This Message was edited by: AntnyMD on 2001-09-04 08:19:38 ]</font>

[redout]

One of my first attempt was following the advice you can find here http://www.geocities.com/seiemezzo/vcd.htm#2 (u can use babelfish.altavista.com to translate it since it's in italian (i'm italian too)).
As u can see the gop is 1-4-2-0, but this didn't help me to generate a working vcd.
I tried even what u can find here (same as above for translation) BUT NO SUCCESS........
I'm going crzy on this issue....

BTW i've tried to use SCK 90 mins media and they work flawlessly in my yamaha 4416s (useful to keep that >160 mins movies on 2 cds)

[AntnyMD]

My suggestion was to set your GOP Structure Tab to 1-4-2-1 (or, change the "4" to "3" although 4 works well for me); then tick ON Close GOP, tick OFF Detect Scene Changes.

If you add any filters in the Advanced Tab, go back to your Video Tab to make sure the framerate hasn't changed. Whenever I add a deinterlace filter in TMPGEnc for those occasionally weird porn DVD rips, the framerate gets changed from my setting of 29.97 to 59.94!

Also make sure your bitrate is somewhere less than 1150, but not exactly 1150, and your audio is 224kbps @ 44.1kHz. In the final System Tab, make sure you have MPEG-1 for VCD selected.

Remember, no matter how good it looks, you cannot use any kind of variable bit rate in your VCD compliant encodes. You must use Constant Bitrate or your CD will not be compliant.

[Sefy]

@AntnyMD, you've mentioned to close the GOP, is this just for TSCV or can I ignore this when using TSCV ? i'm just curious cause i'm trying to write a Chapters Guide, and considering i've never done it before, i'm running into trouble and any help will be appriciated!

[daveP]

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Try lowering the number of B pictures to 4 or less (so that your GOP is about 12-15 pictures or less total per second), and setting your constant/controlled bitrate to 1123, or even 1100.
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Does lowering the bitrate make the VCD non-standard. I remember reading something somewhere saying that segment play items can have lower bit rates, but I thought you needed 1150 for normal MPEG tracks. Can you point me to anywhere that says lower is ok.

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For MPEG-1 video, always tick off Detect Scene Changes, but if you use TSCV or VideoPack 4 for chapters,
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Definitely. this seems to indicate that the NAPA is sensitive to non-default GOP structures. I don't get any stuttering with my DAV309 normally so I can't really test this.
If you lower the number of B frames, this will proportionally increase the number of I frames though, and this might cause the same problems as detect scene change which effectively increases the number of I's.

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always tick on the close GOP option (it inserts a sequence header which is necessary for entrypoints).
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don't you get sequence headers just by setting the "ouput interval of sequence headers" to 1. I can use entry points on my NAPA without specifying closed GOP.

(hope I don't sound to critical here, I'm just trying to figure stuff out myself...)

dave.

[Sefy]

I know this is off topic, but I was told to untick Detect Scene Changes cause it ruins quality, but is it needed for TSCV chaptering ? anyone knows for sure ?

[AntnyMD]

*sigh*

The options I described work for me, but the more I write about it, the more I realize these players (Tanky/Napa) are just extremely sensitive to everything except pressed VCDs. I even made a test disc once that had the following GOP structure: "IBP" ... and it played smoothly. You kind of just have to test things out for yourself to see what works for you on any given encode.

I give up helping!

[daveP]

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On 2001-09-08 06:57:58, Sefy wrote:
I know this is off topic, but I was told to untick Detect Scene Changes cause it ruins quality, but is it needed for TSCV chaptering ? anyone knows for sure ?
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I'm pretty sure it isn't needed for chaptering. It makes really nasty looking VCDs on the NAPA, you get an effect that looks like the frames around the scene are swapped or something.

It probably improves the quality on other players though.

I-frames are full jpeg-style frames as opposed to frames encoded relative to the surrounding ones. So putting an extra I-frame in (which detect scene changes does), should make the quality better because otherwise the encoder will try to find similarities between the two frames either side of the change, and cause they are completely different it will make a bad job of it.

On the NAPA chapters don't seem to work propperly though. Using VCDImager they only work if they are referenced from a menu or something. Software players don't need this so I guess it is just the NAPA being lame.

Oh btw, AntnyMD: I was wrong about using lower bitrates. This is allowed, and two commercial VCDs that I checked used 1140 instead of 1150. It is probably a good idea, but 1150 works ok for me, I must just be lucky.

I might make a NAPA site where people can contribute what works well on it, there are so many combinations of settings and stuff it is pretty annoying waiting about 24 hours to make an MPEG only to find it doesn't work well.

dave.

[Sefy]

I apologise in advance if i'm distracting you guys out of the topic, but i'm curious, why must someone (according to some threads here) demuplex a TMPGEnc encoded file and then re-encode it with bbMPEG so TSCV will find the entrypoints ? why can't it detect them in the file that was just encoded with TMPGEnc ?

[vitualis]

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On 2001-09-08 23:13:53, Sefy wrote:
I apologise in advance if i'm distracting you guys out of the topic, but i'm curious, why must someone (according to some threads here) demuplex a TMPGEnc encoded file and then re-encode it with bbMPEG so TSCV will find the entrypoints ? why can't it detect them in the file that was just encoded with TMPGEnc ?

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Sefy, this reply is in regards to your TMPGEnc settings question before as well.

Firstly, "create bitstream for editing" which means closing GOPs. This is the most important one in terms of "chapters". An entrypoint on a VCD can only placed if there is an MPEG sequence header, the beginning of a GOP (i.e., I-frame) and the beginning of a sector.

Now, if you don't have this ticked, then TMPGEnc won't necessarily close a GOP depending on the video content (i.e., say there isn't much changing on the video). This theorectically (and in reality) means you can have increased video quality because bits aren't wasted in I-frames that don't contribute to anything. However, it does also mean that sometimes a GOP may not be closed and started for several seconds. If you just so happen to want an entrypoint there, it means that the closest entry possible may be several seconds out (which is unacceptable).

Now, as for the "auto insert I-frame" setting, I don't think that this will actually affect the finding of entrypoints (but it may -- I'm not sure). It should be noted that the auto-insertion of I-frames won't necessarily yield better video quality. If the encoder is a little bit "trigger happy" (or the particular video appears to have a lot of new "scenes" to the encoder), then too many I-frames will be added -- effectively draining the bits available for other frames. Leaving GOPs open is probably more significant for video quality as it leaves out I-frames where they aren't needed -- boosting the bits available for other frames (however, it can lead to the entrypoints problem).

As for demuxing and remuxing with bbMPEG, I'm not entirely sure. I encode my MPEG-1 files with Panasonic and then use the MPEG Sequence Maker to add the sequence headers. I then use TMPGEnc12a to remux. I never have any problems with GNU VCDImager finding my entrypoints...

Regards.