Help! I Have a Hi Def Dilemma

[George Tyndall]

Abstract: Of the two HD MPEG2s that I will describe, only the inferior-quality version imports properly into PRE7 for the purpose of burning a Blu-ray DVD, however, the resulting Blu-ray DVD does not look as good as the one that is burned from the HD MPEG2 that does not import properly (it has a number of red frames).

Project: I wish to assemble a roughly 1-Hour HD Movie from a Number of Shorter HD Movies. The shorter movies have been exported in HD MPEG2 format using 2 different methods: 1) the File>Export>Movie command; 2) the Share>PC>MPEG option. With both method 1 and 2, they were output as HD MPEG2 1440x1080, however, I noted the following differences in the details: Whereas exporting the rendered m2t Timeline using method 1 resulted in a Filetype “CompilerMPEGProxy” with the Video Settings “Compressor: I-Frame Only MPEG,” exporting using method 2 resulted in the Video Codec “MainConcept MPEG Video.” In addition, while method 1 resulted in an MPEG file of 2.41GB, method 2 resulted in an m2t file of 2.35GB. When I played each of these back with Windows Media Viewer, they seemed of similar quality–but when I burned a Blu-ray DVD from each of them there were obvious differences between the resulting HD DVDs.

Procedure: I burned 2 separate Blu-ray DVDs from the 2 short HD MPEG2 movies that resulted from methods 1 and 2. I then played each of the two DVDs simultaneously with 2 identical LG computer-mounted Blu-ray players using 2 identical Gateway 24-inch HDTVs that were placed side by side

Result: When I compared the Blu-ray DVDs that result from methods 1 and 2, the latter was of far better visual quality, in terms of both skin tones and sharpness. Why is that a problem?

Problem: When I import each of the HD MPEG2 movies into PRE7 for the purpose of burning a Blu-ray DVD, the better-looking one (2) invariably fails to import properly in that a number of red frames appear on the Timeline. I assume these red frames are called “dropouts,” but I am not sure.* Meanwhile, I get no red frames when importing the MPEG2 that results from method 1, but as I said the resulting Blu-ray DVD does not look as good.

Can anyone explain what is going on with the red frames? Is there a way to eliminate them? Should I use another program, such as ImgBurn or Sony Vegas Movie, to burn the HD MPEG2 movies to Blu-ray?
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*I get the same result when I import the file into PRE4

[Paul LS]

What bit rate did you set for the Share>PC>MPEG2 1440x1080i export, the default or did you set it to the HDV standard of CBR 25Mbps.

Download the trial version of VideoRedo ( http://www.videoredo.com ) and do a QuickStream Fix (under tools) of your MPEG files before importing into PE7 and after exporting from PE7.... before burning to disc. This resolves red/blocky pixels for me.

[George Tyndall]

What bit rate did you set for the Share>PC>MPEG2 1440x1080i export, the default or did you set it to the HDV standard of CBR 25Mbps.

Paul, I accepted the default bit rate, VBR, 1 Pass, but I do see the option to select CBR 25Mbps, so I am going to try that now.

If I still have a problem I will also try the following:


Download the trial version of VideoRedo ( http://www.videoredo.com ) and do a QuickStream Fix (under tools) of your MPEG files before importing into PE7 and after exporting from PE7.... before burning to disc. This resolves red/blocky pixels for me.[/quote]

Thanks for your help!

Addendum: Resetting to CBR 25Mbps seems to have solved the problem, i.e., I don't see any more red frames

P.S. I named the new preset after you.

Thanks again!

Second addendum: I spoke too soon--some of the files do have the red frames even after applying your preset.

BTW,I am not sure what you mean by running that program after exporting from PRE and before burning the Blu-ray, as I burn my Blu-rays with PRE directly from the MPEG Timeline. \

Please advise.

[Paul LS]

Uping the bit rate to 25Mbps should improve your quality issues on your option 2. Even so you still might get some red frames... do they appear red on the PE7 timeline? If so try VideoRedo on your raw clips before importing to PE7.

I burn (to AVCHD HD discs) and so use a seperate burning program. So I will also run the clips through VideoRedo after export and before burning.

[George Tyndall]

Uping the bit rate to 25Mbps should improve your quality issues on your option 2.

Paul, here is the default Preset: VBR, 1 Pass, Min 18.00, Target 25.00, Max 30.00 [Mbps]

When I change the Preset to CBR, 25.00 [Mbps], am I uping the bit rate?

[Paul LS]

VBR adjusts the bit rate according to the frame content, increasing bit rate in frames with fast movement and reducing bit rate on frames which change little. The idea is to minimize the file size but maintain good quality. So really, if it works correctly, you would not see too much difference between CBR at 25 Mbps and VBR with a target bit rate of 25 Mbps. As HDV is recorded at CBR 25 Mbps I just always use that bit rate as it matches the input bit rate and therefore maximizes quality.

[Bob]

Paul's correct. The main purpose for using VBR is to reduce file size while still maintaining good quality. However, to do that, you really should be using two-pass with VBR. The first pass generates data used by the second pass for optimum encoding. One pass VBR won't be as good.

[George Tyndall]

VBR adjusts the bit rate according to the frame content, increasing bit rate in frames with fast movement and reducing bit rate on frames which change little. The idea is to minimize the file size but maintain good quality. So really, if it works correctly, you would not see too much difference between CBR at 25 Mbps and VBR with a target bit rate of 25 Mbps. As HDV is recorded at CBR 25 Mbps I just always use that bit rate as it matches the input bit rate and therefore maximizes quality.

Thanks, Paul, but I'm sorry to say that, with some of the files even after applying your method, I am still getting the red frames.

[George Tyndall]

Paul's correct. The main purpose for using VBR is to reduce file size while still maintaining good quality. However, to do that, you really should be using two-pass with VBR. The first pass generates data used by the second pass for optimum encoding. One pass VBR won't be as good.

Thanks, Bob, I've just reset to VBR, 2 Pass, but before I click Ok should I also move the Quality slider from 4 all the way to maximum=5?

BTW, my sense is that NONE of the various export methods will give me as high-quality a Blu-ray as burning it directly from the PRE7 m2t Timeline. Am I correct?

Also, my understanding is that, if I create an image of that first disc then use the image to create additional Blu-rays, the latter will look every bit as good as the orginal. Is that also correct?

[George Tyndall]

Can anyone explain what is going on with the red frames? Is there a way to eliminate them? Should I use another program, such as ImgBurn or Sony Vegas Movie, to burn the HD MPEG2 movies to Blu-ray?

Eureka!

Thanks once again to the members of muvipix, a problem has been solved.

Specifically, I've found a method for burning a long Blu-ray DVD that is composed of shorter HD Movies but that looks as good as the individual shorter movies when they were burned directly to a Blu-ray disc from the PRE7 Timeline--and the method does not involve the use of any additional software.



And I've just finished describing this method in a new post. Here is the link to that post: viewtopic.php?f=57&t=4959

[Bill Hunt]

George,

Fantastic!

You are correct that an ISO (or other "image") of your BD will result in additional BD's that are byte-for-byte copies. One could also do a burner-to-burner copy via other software, if one had 2 BD burners.

I'm following your efforts, as BD will probably be in my future, within the year. However, for me it will mean upgrading to CS4, new computer, new camera and new OS, so I am not in a hurry to rush into it.

Hunt