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transcoding .VOB files
I’m sure this has to have been covered somewhere, but I’ve yet to find a solution to what should be a basic operation.
I’ve been getting auto-play DVD’s that I need to pull video files from and edit in Premiere. I’m currently in PP Creative Cloud, but I also have CS5.5. Although I can import the .VOB files directly in PP, the frame size is incorrectly interpreted by Premier and cuts off part of the right hand side of the frame. I have tried going to “interpret footage” and change the pixel aspect ratio, which just squishes or stretches the image adding or subtracting black bars but still cutting off the right edge of the frame.
Going into Adobe Media Encoder, I have the exact same problem, although there I could see where the problem was coming from. Even though using other programs like G-Spot or Media Info show the files to be 720X480, Media Encoder is listing the source footage as 540X480.
My temporary fix was to use Media Encoder CS5.5, which correctly interprets the footage as 720X480, although it uses the wrong pixel aspect ratio (the source video is widescreen), which is a quick fix in PP using the above mentioned “Interpret footage.”
So now I have a new problem. What codec to used to use to export the .vob files to work best in PP and look just as good as the source. After a few experiments, I settled on Quicktime files wrapped around DV25 NTSC, but frankly the resulting images looks a bit softer and higher contrast (loosing details in the shadows). I’ve heard AVI is the solution, but uncompressed AVI turns my 1GB files into massive 36GB files. Why doesn’t Adobe have something like ProRes?
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4 Replies
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[Denez McAdoo] “Why doesn’t Adobe have something like ProRes?”
Other supported codecs similar to ProRes include AVC-Intra, DNxHD, and Cineform.
[Denez McAdoo] “So now I have a new problem. What codec to used to use to export the .vob files to work best in PP and look just as good as the source… I’ve heard AVI is the solution, but uncompressed AVI turns my 1GB files into massive 36GB files.”
Here are some intermediate codecs to consider if you are unable to get Premiere to display the VOB files properly:
– MPEG-2 might be the best option given that the source material is VOB. Export using High Profile, High Level, 2-Pass VBR, maximum average bitrate, GOP structure of M=1 and N=1, and 11-bit Intra DC Precision. Keeping the native aspect ratio is OK if you plan to edit and export using rectangular pixels. Square pixels are a good choice, too, but use the 4:2:2 Profile to retain more color information when remapping the pixels.
– PNG or JPEG2000 image sequences offer lossless quality and moderate file sizes. There might be a slight color shift going from 8bpc YCC to 8bpc RGB.
– AVC-Intra and DNxHD only support HD resolutions. You could upscale the source image to 1280×720, or save an 854×480 image in a 1280×720 file. Upscaling to 1280×720 at a high bitrate is a good option only if you plan to rescale during editing.
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Ivan, thanks a lot. I’ll try those out. I tried some of the Avid codex, but not DNxHD because this is SD footage (inherent to being burned to a DVD).
I also tried MPEG-2, though if I remember correctly the results seemed close enough to the DV25 NTSC, that I didn’t bother. Also wouldn’t re-encoding MPEG-2 (as VOB) into MPEG-2 again just be double compression (ie, loosing even more info), or would it be like putting a .zip file into another .zip file, where it’s already done it’s job and won’t compress anymore.
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Hi Denez,
I believe you are on PC, correct?
I know you tried DV25 already, but why the QuickTime? Avoid QT on the PC when at all possible, has its downsides. Why not just use DV NTSC as an .avi file? You ought to have that option available.
Regarding the upscale option, I would recommend against that. You lose quality in the upscale, then downscaling again finishes it off. Two unnecessary conversions.
Thanks
Jeff Pulera
Safe Harbor Computers -
[Denez McAdoo] “I also tried MPEG-2, though if I remember correctly the results seemed close enough to the DV25 NTSC, that I didn’t bother. Also wouldn’t re-encoding MPEG-2 (as VOB) into MPEG-2 again just be double compression (ie, loosing even more info), or would it be like putting a .zip file into another .zip file, where it’s already done it’s job and won’t compress anymore.”
Files are compressed using encoders, but encoding does not always compress a file. It is not a ratio where the file shrinks every time. Think of encoding as trying to fit a set of data into an envelope. The size and shape of the envelope will be determined by the encoder settings. When the source footage is highly compressed (i.e. a small envelope), intermediate copies should be made using a larger envelope in order to reduce generational losses in quality. The MPEG-2 settings listed in the previous post create a bigger envelope than standard DVD settings. This does not improve the quality of the source material, it just minimizes the risk of degradation.
Premiere Pro does not have pass-through functionality; the footage is expanded and then re-compressed. I think you are more likely to see generational losses using DV than a low compression MPEG-2 copy. YMMV. The best approach is to test different codecs at multiple settings.
Personally, my first choice would be to edit using the VOB files. Otherwise, I would convert the SD footage to uncompressed YUV or DPX. High bitrate 4:2:2 MPEG-2 is a viable option for YCC SD material when file size is a consideration.
[Jeff Pulera] “Regarding the upscale option, I would recommend against that. You lose quality in the upscale, then downscaling again finishes it off. Two unnecessary conversions.”
I agree; there is no need to upscale the intermediate file if there is no plan to rescale the final output. If the final output is going to be upscaled, though, I prefer to create the intermediate file at the final output resolution rather than upscale an SD copy later.
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