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Archival of H.264 / AVCHD
Hi everyone,
I have some questions about archival workflows for the more heavily compressed video codecs. The biggest question being – does H.264 / AVCHD being long-GOP significantly effect the reliability of an archive?
Backstory: I’ve been shooting primarily in H.264 / AVCHD for about 5 years. In that span of time, I’ve always had pretty much the same workflow – I would transcode to ProRes 422 or LT for the edit, and for archival I would media manage the ProRes, trash all other ProRes, and hold on to all the original “raw” H.264 / AVCHD files.
I thought this was a fine workflow, but recently I had a project that forced me to really go into the archives to pull out footage that was 3 or 4 years old. I needed to find media that was part of the raw footage, not in any media managed edits. I was shocked to see that that a ton of my raw H.264 files had been corrupted – huge chunks of the files (if not all of them) were reduced to a pixelated mess in which you could usually just barely make out the original image.
It is making me question my whole archival workflow – since I convert everything to ProRes for the edit, for archival should I trash all my raw media out of the camera and hold on to all the ProRes for archival? This seems way less practical to me, but possibly a necessary solution. With the type of work I do, I need to hold on to everything. Does it make no sense to backup long-GOP compressed media if you’re worried about long term archival?
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3 Replies
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I am unaware of any reason why file format would make a difference with respect to longevity. How were the archived files stored, and were the problems related to the storage media? As a general statement platter discs are more reliable than memory cards for long term storage. Also, it is a good idea to have a backup copy of your archives stored in a different location.
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i’m not trying to insinuate that i think one codec inherently has a longer lifespan than another, rather i’m wondering if certain codecs are *less susceptible* to hard drive related errors than others. and yes, this was definitely a hard drive related error.
though i’m not a technician, i could theoretically definitely see there being a correlation between file format and longevity – e.g. if a codec is long GOP, couldn’t having an error in 1 keyframe potentially throw off other reference frames? i wondered this because this is actually what appeared to be happening in my corrupted files – the image would scramble in a way where it looked at though the codec couldn’t completely interpolate between frames correctly.
basically, i’m trying to determine if archiving in ProRes is a safer codec for long-term archival than h.264 / avchd because it’s intraframe, which given my understanding of it is likely.. i was just hoping someone could either corroborate this or debunk it so i save tons of hard drive space.
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I think archiving on spinning discs is the issue, not necessarily the codec. I see no reason why you could not archive the H264 media as you have been but to LTO which is designed for long term storage.
Regardless of codec, a hard drive problem can corrupt media. So your options of H264 vs Prores does not solve the weak point in your archiving process.
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