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Old 11th May 2013, 19:42   #21  |  Link
nhakobian
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Join Date: Oct 2009
Location: San Francisco, CA
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Quote:
Originally Posted by msp1518 View Post
AVI's are pretty much the best to work with, but I am normally given MKV's. It makes me insane. What is it with the love for MKV's?
AVI's have many technical limitations. The format was designed 20+ years ago, before many of the modern video codecs were even thought about. The first (and foremost) issue is that it can't support filesizes above 4GB (and in some cases I believe that is 2GB). For many cases this is a big deal.

AVI's don't have internal support for B-frames and out-of-order decoding (which, if my memory serves me correctly, is why B-frames are unsupported). There have been "hacks" for certain formats to make them work in AVI's but they are not universally supported, and not part of the standard.

AVI's also only support fixed frame lengths. I.e., there is no support for per-frame individual timecodes. While most distributed files only contain a single framerate, there are many cases where it is necessary.

So, why MKV? Its an independent and "open" container format which is simpler than MP4. I'm not sure if the latter point has had really any impact on its adoption, but recently many devices and companies are openly supporting it such as Google with its WEBM format (which is MKV with restrictions).

In my experience I've found that Non-linear editors generally have really bad support for many video formats except for a small number with specific codec combinations that may or may not be documented. It might be easier to re-encode the incoming footage into an intermediate format for editing. I know at least one professional editor who does this for much of her incoming material (sometimes she encodes a low bitrate / frame size for easier editing, then only swaps in the original for the final export).

The "stuttering" you mention while working on a video until you export/render it might be due to the incoming video file having long GOP sizes. If you are srubbing your timeline for a specific position, and that position happens to be in the middle of a GOP, the decoder has to decode the whole (or at least part of) a sequence before your frame can be displayed. You probably don't notice this with AVI files since fewer frames have to be decoded to seek to a specific position. This can be reduced or eliminated by re-encoding the video using only I-frames in MKV/MP4, but the file sizes will be much larger than the source files.

With audio being slightly delayed in AAC files, I believe that there is a fraction of a second of silence at the beginning of each file, which, if you don't delay by, will be noticeable if trying to resync the audio/video manually. There was recently a thread in one of the audio forums which discussed this extensively (unfortunately, I can't find it at the moment).

Hopefully some of this can point you in the right direction or maybe give some insight into why certain things are used. There are a lot of utilities that are out there at significantly varying technical levels, and it can be difficult to figure out which one is the best to use. From my experience, while the lower level command-line utilities have a much steeper learning curve, it worth while to spend the time learning them. The "front end" utilities sometimes gloss over certain details or make assumptions about your material that aren't universally applicable.
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