Composite mpg file very poor quality

[Longshanks]

Hi

Am still using VS12 so appreciate much superseded by newer products etc. Have been using this with my Panasonic SHDR 86 for ages to produce our holiday projects.

Normally I divide project into smaller video files which can then go onto 2/3 DVDs. However, for the first time ever I tried DL DVDs (Verbatims) as that would allow me to put all of my project onto one of these. (6.8gb)

The project took about an hour to convert and burn but the result was terrible (some blurring distorted etc) I was about to condemn the DLs but decided to check the video file first. To my surprise it was this that had the poor quality and not the conversion process or DLs. My Camcorder defaults to mpg 4 if I use the hard drive so the I then convert the individual clips to individual mpg 2. I then put into timeline and edit b4 creating the 6.8g file as above. It is evident that the individual mpgs are fine but not the composite.

Is there an obvious reason for this result? Is 6.8gb too big anyway?? (Don't believe it's connected to mpg 4 conversion as been doing this for ages and individual files fine)

Finally, should have said that video properties are those I've used for eons.

Sorry for the war n'peace but wanted to get it all out as they say.

Thanks for your time.

[Ken Berry]

My Camcorder defaults to mpg 4 if I use the hard drive so the I then convert the individual clips to individual mpg 2.

How do you convert them -- with VS 12? Or with a third party conversion program? I would personally be using the latter. Some of us here use a free converter called Format Factory. A Google search will find it. Just be careful when installing it to say NO to its offers to install other unwanted bloatware...

It is evident that the individual mpgs are fine but not the composite.

I'm not sure I really understand what you mean here. Which individual mpgs are fine -- the original mp4 or the converted mpeg-2? What do you use to deduce that this is "evident"? And what exactly do you mean by "composite" -- the converted files themselves, or the edited project which you have converted into a new video before putting it in the burner?

Apart from having an ancient version of VS, it would also be useful to know something about your computer and the version of Windows you are using.

[Longshanks]

Ok thanks. Here goes.

1. I'm not at home right now but use Third Party which I've used for eons with no issues as stated. Conversion process also good to go as individual mpg 2 files good as indicated.
2. "Individual mpgs" represents those files produced by the mpg 4 converter. The original mpg 4 files are fine as are the mpg 2 files created. " Composite" here means the aggregate file created when I put all those above into timeline to work on and then produce a single file (same properties as individual ones). Think I also described this earlier. Ergo the 6.8mpg 2 would be the composite.
3. Use Win 7 on Dell XPS 420.
4. Thought I got my retaliation in first with my oblique reference to age of prog.

Thank you.

[canuck]

So what are the settings when you merge the individual mpg files into the final mpg file? There should be no difference in quality between the indivual mpgs and the final mpg since no re-rendering should be required if you used the correct settings.

How long in time is your project?

[Longshanks]

Not home so will check but have always applied same bit rate, audio settings etc.

It's 6.8 mpg as stated and about 2 hours 40 (Ergo rationale for DL DVD)

Understand that it shouldn't be a rendering issue etc.

Thanks

[Ken Berry]

Also check whether you have SmartRender enabled or not. If enabled, try rendering with it disabled -- or vice versa.

[Longshanks]

Will try tomorrow.

Many thanks for clear and helpful advice.

[canuck]

Not home so will check but have always applied same bit rate, audio settings etc.

It's 6.8 mpg as stated and about 2 hours 40 (Ergo rationale for DL DVD)

Understand that it shouldn't be a rendering issue etc.

Thanks

A DL DVD can only contain less then 2 hours of mpg video at the best quality setting. Since you are trying to put 2hr40min on that DL DVD, the quality will be reduced since it would require a much lower bitrate.

[Longshanks]

I said earlier that the DL DVD was not the issue as the composite mpg 2 file was degraded b4 burning to disk.

[canuck]

For 2hrs40min of best quality mpg video your file should be over 10GB. Since it is only 6.8GB, you are obviously using reduced bitrate which means lower quality

[Longshanks]

That's bizarre as I used 8000 bit rate and max quality so strange that only equated to 6.8 rather than 10gb.

I keep saying not at home so will check specifications tomorrow and report back.

I also note you are introducing two aspects:

1. Amount of top notch video accommodated on DL disk.

2. Size of mpg file duration 2 hs 40 mins when burnt at best bit rate.

I guess two manifestations of same thing?

[Ken Berry]

You could have entered 8000 kbps manually, but as canuck said, if VS was presented with a 2 hr 40 minute project it would calculate behind the scenes that 8000 kbps was too high and automatically set out to reduce the bitrate. Unfortunately, when VS does this automatically, it does not reduce along a smooth sliding scale; it uses fixed drops with nothing in between. Given that the final disc has 6.8 GB instead of something closer to what a dual layer DVD can hold (notionally, 8.3 GB) it seems pretty clear that the automatically imposed bitrate was closer to 4000 kb which at best can only give quality which is somewhat similar to VHS tape. If you want to get a larger size closer to 8.3 GB, you could manually set the bitrate to around 6000 kbps or just a little bit higher and see what the quality is like then.

[Longshanks]

Thanks again. I'm with you on final advice apart from ref to VS "deciding that 8000 Kbps bit rate was too high". Too high or big for what when we're only talking about creating a video file rather than containing that on on a disk?

I also have some new info. The duration is 2 hs 5 mins not 2 hs 40 mins. The mpg converter prog used a variable bit rate to produce the individual mpg 2 files whereas the composite properties show "variable bit rate max 8000 Kbps. The mpg 2 converter I use is "Video to Video by Media Converters". I didn't change the default settings but the outcome was variable bit rate as indicated above.

I'm following Ken's advice in rendering another video file using 6000kbps and will report back.

Many thanks.

[Ken Berry]

Too high or big for what when we're only talking about creating a video file rather than containing that on a disk?

Thanks for the extra info regarding the real length of the project. As for the quote above, you miss the point as to what bitrate represents. Essentially, bitrate represents quality but it also represents size of the file. With a one hour project, an 8000 kbps bitrate will produce a video file which will fill almost exactly, with a little to spare (depending on the audio format chosen) onto a single layer DVD (4.3 GB) or two hours to fit on a dual layer disc. That is at the highest quality for a DVD. (While you can set a higher bitrate, over 9000 kbps, a lot of stand-alone DVD players have great difficulty playing home made DVDs using a bitrate over 8000 kbps.)

If you reduce the bitrate, you reduce the quality but you also reduce the size of the file you are producing to burn to disc. So using 6000 kbps will produce a file roughly two thirds as big as with 8000 kbps -- so you can burn a DVD with roughly one third more video on it, but with reduced quality; though with that bitrate, the quality should still be quite high. And with a bitrate of 4000 kbps, you can produce a video with roughly twice the length as one with 8000 kbps -- but the quality will probably be half or less as well.

If your project is in reality 2 hours 5 minutes, I would be tempted to use a bitrate of 7500 kbps just to see what happens -- though notionally, if you have chosen Dolby audio, a bitrate of 8000 kbps should still produce a final video which will fit on your DL disc. But that should be producing a file over 8 GB in size, not your 6 GB size one. So something has gone wrong there somewhere, and I still suspect it had something to do with VS applying an automatic reduction in the bitrate to allow the entire project to be burnt to disc. And as we have been at pains to explain, a reduction in bitrate -- especially one which has reduced the final size so significantly -- will also affect the final quality equally significantly.

[asik1]

my 2 cents will be, if it's 125 minutes recut it to 110.