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AVI - MPG2 - Getting Jerky Video

 
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Zodiac



Joined: 13 Mar 2005
Posts: 10

PostPosted: Sun 13 Mar 2005, 7:31    Post subject: AVI - MPG2 - Getting Jerky Video Reply with quote

Hi, I have captured AVI from my MiniDV tapes which are about 9GB each for 60 mins of video. I now want to put these on DVD and using TMPGEnc to encode to MPeg2. However the final result is video either with Jaggy edges or with Jerky Motion, when then video has lot of motion in it the frames are Jerky .. i can feel the its not smooth movement and irritates the viewer. This is not there on the AVI if i play on computer.
My input video is NTSC and output is PAL if that makes any difference in analaysis of problem.

My problem is both on computer and TV.
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RMN
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Joined: 04 Feb 2003
Posts: 587
Location: Lisboa, Portugal

PostPosted: Sun 13 Mar 2005, 16:46    Post subject: Reply with quote

Converting from PAL to NTSC is not a simple thing, due to different frame rates and interlacing. Virtually all DVD players can play both PAL and NTSC these days; I would suggest making the DVD with the same standard as the source. Even if you make a correct conversion (with a specialised program, or doing all the steps manually), you will lose a lot of quality.

also, always make sure you test the result on a TV or video monitor; software DVD players will hide a lot of interlacing problems, but when you play it on a TV, the problems will be there.

RMN
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Zodiac



Joined: 13 Mar 2005
Posts: 10

PostPosted: Mon 14 Mar 2005, 15:01    Post subject: Reply with quote

thanks for reply .. however i really dont think there will be loss of quality if i convert NTSC to PAL .. If i dont convert to PAL then my TV wont see colors .. i agree that DVD player will play both but the output signal on video out will still carry NTSC signal and my TV will not understand the colors .. am i right in saying this ?? because one of my TV is not multisystem when it comes to Video .. RF in is multi system.

More over the problem is not of interlacing .. what i see ia Jerks in video when camera is moving .. i have tendency to move camera very fast while shoooting (which is bad thing) so video there becomes quite jerky and irritates eyes
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RMN
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Joined: 04 Feb 2003
Posts: 587
Location: Lisboa, Portugal

PostPosted: Mon 14 Mar 2005, 16:57    Post subject: Reply with quote

Yes, you will lose quality when converting between the formats, for two main reasons:

1. The image will need to be resampled, because its vertical resolution is different. This will always cause a loss of quality (slight blur and possibly a "moiré wave" pattern, depending on the resampling algorithm) and, when resampling interlaced footage, you can also get some "shimmering" (scintillation) in thin horizontal details.

2. PAL and NTSC have different frame rates. When you convert from NTSC to PAL, you immediately lose 20% of the frames (29.97 -> 25 frames per second), and motion loses some continuity (because, instead of having the same interval between frames, you now have 5 frames captured 1/30th of a second apart, and then one with an interval of 1/15th of a second). This makes the motion less fluid and slightly unpleasant.

Good conversion algorithms will try to minimise both problems (by analysing the image, using motion compensation, working at twice the frame rate and re-interlacing at the end, etc.), but it will never look quite as good as the original.

Most TVs made in the last 10 years can display an NTSC signal properly (it's cheaper for the manufacturers to have a single model than to make different models for different countries). If your TV can't, and you really need to convert from PAL to NTSC (or vice-versa), then you have three possibilities:

1. Do it with a program that is designed specifically for it. There are some programs (ex., DVConverter, Standards Converter, etc.) that will simply take an NTSC DV file and output a PAL file. Some programs are better than others, of course, so try the demos. This is the simplest method but I'm not sure if any of these programs are free.

2. Do it manually, step by step. Here are some guides. Some will give you better quality than others, but involve more work or extra software.

3. If you don't mind squashing the image vertically, you can tell TMPGEnc to keep the original size, and change only the frame rate (if you change the size, the image will always have jagged edges, because TMPGEnc can't resize interlaced footage properly). To do this, go to the "Advanced settings" tab and select "Source aspect ratio: 1:1 (VGA)" and "Video arrange method: Center". You will have to make a test to determine the correct field order, since centering the image might cause the first line to shift fields (it probably won't, but it depends on how TMPGEnc aligns the image). This will not solve the motion fluidity problem but as long as you avoid the vertical resampling, you should not have any interlacing problems.

RMN
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Zodiac



Joined: 13 Mar 2005
Posts: 10

PostPosted: Mon 21 Mar 2005, 4:32    Post subject: Reply with quote

Hello Rmn, thanks for the detailed explanation i understood what u are trying to say and now fully agree with you. So i wont make attemp to convert from NTSC to PAL since i want to preserve the best i can Smile .. but the Jerky movements is issue even if i am not converting from NTSC to PAL and simple converting from DV (AVI) to Mpeg2 using TMPGenc.

I have tried many different setting but i feel the best restults and in least processing time i am getting is at CBR of 8000 .. it gives me about 3GB file for about 50 min of Video. Now my second question is how come the commercial DVD files (the VOB) are about 4 GB for appx 120 Min of Video and still have better looking quality then mine.

Another question is that i have captured Vegas recently using inbuilt 16:9 feature of my Sony Handcam PC 101, when i play these on my TV directly it still plays in full screen .. i am yet to capture it on my PC and convert to DVD.

I am also in need to include some good backgrounds with music .. TMPGenc author seems to be missing the music in menu background .. i want to use DVDLab (at least try) however it expect me to provide them the background with music in form of AVI or Mpeg file .. is there any site to have such a file or any guides to built the same.

Another question .. sometimes i use Ulead DVD movie factory 3, its easiest to make motion menu etc ... however even if i provide this software the Mpeg2 (instead of AVI) files in the project it still will do the video conversion process .. which means the earlier process i did using TMPGenc (AVI to Mpeg) is a waste .. i rely more on TMPGenc then DVD MF since it gives me more flexibility .. i have also tried checking the option "DO not convert Compliant Mpeg files" but it still will convert .. any suggestions on this ?
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RMN
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Joined: 04 Feb 2003
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Location: Lisboa, Portugal

PostPosted: Tue 22 Mar 2005, 0:13    Post subject: Reply with quote

Zodiac wrote:
but the Jerky movements is issue even if i am not converting from NTSC to PAL and simple converting from DV (AVI) to Mpeg2 using TMPGenc.


Are you playing the resulting DVD on your PC or on a set-top player?

What are your TMPGEnc settings (namely resolution and interlace mode)? Are you applying any filters in TMPGEnc?

Zodiac wrote:
Now my second question is how come the commercial DVD files (the VOB) are about 4 GB for appx 120 Min of Video and still have better looking quality then mine.


Commercial DVDs are 9 GB, not 4. Anyway, film can be more compressed than video and still have better quality. This is mostly due to three things: First, film is not interlaced, and non-interlaced footage is easier to compress (jagged lines need more bits). Second (and this is the main reason), film has much less noise (grain) than video, so the encoder doesn't need to waste any bits "preserving" the grain. And third, film DVDs are often encoded at 24 fps, so they can save some space when compared to NTSC video DVDs (for PAL the difference is very small).

Zodiac wrote:
Another question is that i have captured Vegas recently using inbuilt 16:9 feature of my Sony Handcam PC 101, when i play these on my TV directly it still plays in full screen .. i am yet to capture it on my PC and convert to DVD.


What do you mean by "full screen"? You mean the image is stretched vertically? If so, that is a good sign - it means the camera is recording "real" 16:9 and not simply cropping the image. You need to switch your TV to 16:9 mode (some will switch automatically, some can't switch at all).

When making the DVD, simply select 16:9 as the source and output formats.

Zodiac wrote:
I am also in need to include some good backgrounds with music .. TMPGenc author seems to be missing the music in menu background .. i want to use DVDLab (at least try) however it expect me to provide them the background with music in form of AVI or Mpeg file .. is there any site to have such a file or any guides to built the same.


The DVD standard doesn't support the concept of background music. If you want sound in your menus, you need to use animated menus (even if all the frames are identical). Video DVD players will only play audio if they are also playing video. So just create an AVI that simply repeats the same frame for the length of the music.

Zodiac wrote:
Another question .. sometimes i use Ulead DVD movie factory 3, its easiest to make motion menu etc ... however even if i provide this software the Mpeg2 (instead of AVI) files in the project it still will do the video conversion process .. which means the earlier process i did using TMPGenc (AVI to Mpeg) is a waste .. i rely more on TMPGenc then DVD MF since it gives me more flexibility .. i have also tried checking the option "DO not convert Compliant Mpeg files" but it still will convert .. any suggestions on this ?


Are you importing system streams (audio+video in one file) or elementary streams (separate files)? Some programs will recompress if they don't like the audio format. Importing the video and audio in separate files usually avoids this.

Also, try using closed GOPs, and make 100% sure that you have the "sequence header" option in TMPGEnc set to 1.

If none of that works, try sending an e-mail to Ulead's user support. Maybe they are aware of the problem and know how to work around it.

RMN
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