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Transcoding advice: Frame rate and Codec at the same time?
So I’m transcoding about 50 clips from DVCPRO HD 720p60 59.94fps (960×720) to 720p24 to make the frame rate 23.98fps to match the rest of the film. However, I also have some shots which are HDV 1080p24 23.98fps (1140×1080). Can I just throw on the DVCPRO HD 720p24 encoding to both?..to change just the frame rate of the DVCPRO stuff and also change the HDV codec to DVCPRO…
Are the different frame sizes, 960×720 and 1140×1080, going to be an issue? The entire rest of the film is at 960×720 so it seems probably a good idea to keep that.
Thanks!
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5 Replies
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If you are transcoding, forget about DVCProHD, unless you have to deliver on that format.
Go to PRORES, and with standard HDTV size: 1920×1080 or 1280×720 SQUARED PIXELS.
Rafael -
Rafael, I may decide to do that but I really just want everything to match right now so I can send the film to post so they can finish the audio mix..then I have to send to color to finish and was thinking it would be best to transcode to my final after color..or maybe right before sending to color…I assume you can transcode something more than one time??
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Hi David,
In my opinion, it is best to minimize the number of transcodes, and use as many bits as possible on each pass – isovideo does 10-bit transcoding I/O on Viarte for example, and even more (16-bit internal computations) for standards conversion, including scaling. In general, each time you transcode, you will lose some image quality due to lossy compression (unless you use lossless compression). Therefore it is good practice to conform all your frame-rates and sizes before doing audio mix and color.
Best
Keith -
As Keith say.
One of the rules of thumb of postproduction is trying avoiding re-compression.
If you have to convert, render, process your footage, do it to codec the less possible compressed and keep all the workflow on that codec till you compress again for final delivery.
Some time ago this was complicated by the huge file size of the uncompressed codecs, now is feasible with codecs like Prores.
DVCHDpro was the state-of-the-art codec, but is a very compressed for today standard.
rafael -
Rafael, I understand the concept of not wanting to compress too many times as it will degrade the quality of the footage. However, it also seems that if my 720p clips are never going to get any better resolution then why am I needing to convert these up to the better codec (apple prores 1080p)…the reason for going up to 1080p is because I have a few shots which are HDV 1080p24 at 23.98fps (but only about 10 clips). But it seems like it might make more sense to transcode those clips down to DVCPRO 720p to actually match the quality of all the other 720p stuff and THEN uprez everything to 1080p at the very end for my final output. Again, if the quality of the 720p stuff is not going to get better than why not convert the few shots of the higher resolution to match it??
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