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TMPGENC Problems - blocks / image corruption
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Henry



Joined: 08 May 2003
Posts: 13
Location: Hong Kong

PostPosted: Thu 8 May 2003, 9:35    Post subject: TMPGENC Problems - blocks / image corruption Reply with quote

Hi,

I've used TMPGEnc 2.511.51.159 to do conversion for my AVI (captured from my Sony DV using Ulead VS 7.0) to DVD MPEG2. All settings I have followed the recommendation in this web site. However, I still get some blocks in some snapshots (may be in static or motion part). I get frustrated after doing a lot of settings change but also find that the converted MPEG2 is having blocks.

Please help. Thx a lot. Crying or Very sad
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Henry



Joined: 08 May 2003
Posts: 13
Location: Hong Kong

PostPosted: Thu 8 May 2003, 10:20    Post subject: Reply with quote

Hi,

I enclose the problematic snapshot (you can see there are some blocks inside the red circle I added):


I also enclose my TMPGENC settings:





Thx for your all help.
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Josse



Joined: 29 Apr 2003
Posts: 9

PostPosted: Thu 8 May 2003, 20:07    Post subject: Reply with quote

Hi Henry,

Unfortunately Yahoo won't show me the pictures you linked, but even without seeing those: what kind of bit rates have you been using? (min, max, average)
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Henry



Joined: 08 May 2003
Posts: 13
Location: Hong Kong

PostPosted: Fri 9 May 2003, 0:50    Post subject: Reply with quote

I m sorry that I just know that the posted pictures from yahoo can't be seen. Anyway, the following are my settings of TMPGENC:
- 2VBR mode, with avg=600, max=8000, min=2000
- Video format=PAL
- Encode mode=Interlace
- DC component precision=10 bits
- Motion search precision=Highest quality
- Video source type=Interlace
- Field order=Top
- Source aspect ratio=4:3 Display
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Josse



Joined: 29 Apr 2003
Posts: 9

PostPosted: Fri 9 May 2003, 1:54    Post subject: Reply with quote

Just to make sure: the "avg=600" is a typo, right? Otherwise the entire stream would have probably been encoded with 2000Kb/s (the minimum setting) which is really low.

If it is "avg=6000" then I can't see anything in the settings that would produce an MPEG stream with lots of artifacts. Unless your material consists almost entirely of hard to encode material. In that case there would be too little moments to drop the bit rate below 6000, which in turn wouldn't allow the bit rate to be raised to 8000 where needed.
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Henry



Joined: 08 May 2003
Posts: 13
Location: Hong Kong

PostPosted: Fri 9 May 2003, 5:36    Post subject: Reply with quote

Josse,

Thx for your explanation. Yes, the avg should be equal to 6000. In fact, I have re-captured the AVI from my Sony DV. There is no problem during AVI playing. However, after conversion, MPEG will have the block problem.

I have retried to post another picture for reference (please refer to the unwanted blocks inside the red circle):


Thx for your help.
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RMN
Site Admin


Joined: 04 Feb 2003
Posts: 587
Location: Lisboa, Portugal

PostPosted: Fri 9 May 2003, 15:27    Post subject: Reply with quote

That whole image looks rather strange. First, its size is 553x442, which is not a standard video resolution. Second, the colours look seriously quantised (i.e., you can notice the steps in the colour gradients), as if it had been converted to 8-bit. And finally, there are the blocks.

Where did you capture that image from? If you have PowerDVD, try opening the .M2V file you created with TMPGEnc (in PowerDVD), play it, locate the frames with the blocks and use the "capture frame" button to save the frame exactly as it appears. Then post one of those frames here (or put it online somewhere and post the link here, or send it to me by e-mail).

I very much doubt those blocks were generated by the encoding process ("encoding blocks" don't normally look like that, they look blurred and "flat"). Those look like playback errors, caused by media problems. And these can be happening either when reading the DV tape (I've had very similar problems with Panasonic tapes recorded in hot days - they don't seem to like the heat), when reading the resulting DVD, or when reading from the hard disk (though this is less likely).

If you play back the M2V file in PowerDVD and the blocks aren't there, then the problem is is the disc itself. Try a different brand of DVD-R (or DVD+R, or whichever format you're using).

If you play back the .M2V file and the blocks are there, try playing back the original DV AVI file, and see if it has the blocks too. If it does, you need to capture the video again, and hope the tape isn't permanently damaged.

If the blocks are in the .M2V file but not in the AVI, then it's prossible you have a hard disk error (bad sectors / messed up cluisters / etc.). Run a full disk scan (with the option to "attempt recovery of bad sectors").

It's not totally impossible that the blocks are being caused by some (very weird) encoding error, but I think the possibilities I described above are more likely.

RMN
~~~
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Henry



Joined: 08 May 2003
Posts: 13
Location: Hong Kong

PostPosted: Mon 12 May 2003, 1:10    Post subject: Reply with quote

RMN,

Thank you for your advice. Let me update what I have performed on MPEG2 conversion in TMPGEnc but blocks are still occassionally occurred:

- Tried Sony or Panasonic DV tape
- AVI file is created under either Ulead VS6.0 or VS7.0
- Blocks do not occur in the AVI file
- Tried 2 physical harddisk
- Tried 2-pass VBR, CBR or CQ
- Blocks also occur even using Ulead Movie Factory2 conversion (directly from AVI to build a DVD)
- Blocks are displayed everytime at the fixed locations when playing a MPEG2 file (using one bitrate setting). When using another bitrate setting, blocks are changed to occur in another fixed locations (I dont know why?)

Based on your advice, I re-enclose the snapshot (please refer to the blocks inside the blue circle. The blurred picture is normal because it is moving quickly.)


Please help. Many thanks.
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RMN
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Joined: 04 Feb 2003
Posts: 587
Location: Lisboa, Portugal

PostPosted: Mon 12 May 2003, 5:45    Post subject: Reply with quote

From what you said, I presume the blocks occur both when playing back a DVD-R and when playing back the MPEG-2 video file (directly from your hard disk), correct?

Have you tried playing the resulting DVD (or the MPEG-2 file) on other systems, or with other programs (ex., both PowerDVD and WinDVD)? Have you tried playing the DVD on a stand-alone (set-top) DVD player? Do you also get the blocks? If so, always in the same place?

The fact that you get blocks both on file created with TMPGEnc and on files created with MovieFactory's encoder reinforces my suspicion that the problem does not lie in the encoding.

Those blocks look very much like file corruption. Notice how those blocks have a "normal", non-pixelated image inside them, but are drawn in the wrong part of the image. This is typical of a decoding error (usually caused either by a corrupt file or a read error). It can also be caused by an encoding error in the motion vectors, but it's very unlikely that TMPGEnc would produce such an error, and even less likely that two different encoders would produce the same kind of error.

The problem with video files is they're too big, otherwise I'd ask you to send me a "blocky" MPEG plus the original AVI, so I could make some tests. What kind of internet connection are you on? If you manage to reproduce that error in a short clip (i.e., something under 1 second), send me the original AVI by e-mail (click on the "e-mail" button below) or put it online somewhere and I'll download it.

RMN
~~~
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Henry



Joined: 08 May 2003
Posts: 13
Location: Hong Kong

PostPosted: Mon 12 May 2003, 10:11    Post subject: Reply with quote

RMN,

Thx a lot. Yes, the blocks occur under all situations - MPEG2 file (read from Windows Media Player, PowerDVD or WinDVD), DVD+RW (read from PC or standalone DVD player), and VOB file (read from PC). The blocks are in the same place. Please note that the locations of blocks will change to another place if I use the other settings in TMPGEnc (I don’t know why?).

Let me cut my AVI file to smaller size and send/ftp both AVI+MPEG2 to you for assistance.
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Henry



Joined: 08 May 2003
Posts: 13
Location: Hong Kong

PostPosted: Tue 13 May 2003, 9:51    Post subject: Reply with quote

RMN,

I feel very frustrated.

I cut my AVI file into a smaller size (~18 seconds in 65MB size) and did my MPEG2 conversion. As expected, the blocks occur based on the settings of TMPGEnc. However, it is interested to find out that when I perform the MPEG2 conversion using old PC (Celeron 733, 10G), the resulted MPEG2 file is in high quality and does not contain unwanted blocks.

For your information, my original PC is AMD Althon1G with 2 harddisks in 40G and 80G. Do you think that the ‘block’ effect is caused by the PC/CPU problem?

Thanks for your help.
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RMN
Site Admin


Joined: 04 Feb 2003
Posts: 587
Location: Lisboa, Portugal

PostPosted: Tue 13 May 2003, 16:16    Post subject: Reply with quote

Ah. I was sort of expecting that. Smile That's why I wanted the AVI file (to try encoding it on another system). I doubt you have a CPU problem (it's not impossible, especially if it's getting too hot, but it's unlikely), but I suspect you have a memory problem.

For the last 5 years or so, memory errors have become by far the most common hardware problems. Too many manufacturers, very low prices, everyone tryng to cut costs, and naturally the quality suffers. An error in the memory is very hard to detect (unless you have ECC memory, and normal home systems don't), and will usually be transferred to the disk, when the data is saved (it won't cause a disk error, but the data saved to the disk will have errors).

I recommend using the program MemTest86 (if that link is too slow try this one) to run a full check on your RAM (it can take several hours). It runs without an operating system, so it can test all areas of memory. If MemTest86 reports any errors, replace your memory ASAP, before you get corruption in some important system file, and can't boot at all.

Follow the installation instructions; MemTest86 will not run from within Windows; you need to run the program to create a boot floppy, and start your computer with that (this is necessary because Windows restricts access to some areas of the memory, and MemTest86 needs to test all addresses).

If MemTest86 doesn't report any errors, try running a hardware monitoring program to see the temperature of your CPU. If it gets too hot (which can happen if the case isn't well ventilated), it may produce floating-point maths errors.

RMN
~~~
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Henry



Joined: 08 May 2003
Posts: 13
Location: Hong Kong

PostPosted: Wed 14 May 2003, 0:47    Post subject: Reply with quote

RMN,

Thx for your explanation. I will try to perform some tests on RAM, CPU and harddisk. I will revert my final results anyways.
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Henry



Joined: 08 May 2003
Posts: 13
Location: Hong Kong

PostPosted: Thu 15 May 2003, 5:25    Post subject: Reply with quote

RMN,

To speed up the checking on my original pc configuration, instead of running your suggested memory testing program, I have replaced my old 256MB RAM (Hyundai) by a new 256MB RAM (Kingston). Interestingly, my pc bios (where motherboard is Magic Pro) interpretted that it is a 512MB RAM!!!! Having installed this pseudo-512MB RAM, my Win XP is running smooth without PC hang problem. However, the block problem still persists. My next step will use a new harddisk and install Win XP again. Hope the block problem can be resolved.
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RMN
Site Admin


Joined: 04 Feb 2003
Posts: 587
Location: Lisboa, Portugal

PostPosted: Thu 15 May 2003, 16:49    Post subject: Reply with quote

Changing things or re-installing things before identifying the error doesn't "speed up" anything, it just adds to the confusion. Do things one step at a time and move to the next thing only after you're sure the present thing is ok (or not ok).

If your motherboard detects 256 MB as 512 MB, there must be some problem in the memory controller. With any luck, it will be detected by MemTest86. If you get an error at a certain address with one memory stick, then replace it with another stick and get an error at the same address, that would indicate a problem in the memory controller (it's very unlikely that two sticks would have a problem at exactly the same address). Unfortunately, the only way to replace the memory controller is to replace the motherboard.

On the other hand, if MemTest86 doesn't detect any errors, then the problem is not in the memory, and is either in the CPU (ex., getting too hot, which often causes floating-point errors) or a software problem (ex., corrupted chipset drivers).

P.S. - This is pretty obvious, but sometimes the most obvious things are the ones we forget: previous tests have shown that the errors are in the files, so playing back those files will always produce the same errors. To test if the system is working correctly you need to encode the AVI clips again. I expect that's what you did (instead of playing the old M2V files).

RMN
~~~
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