B-Roll: File formats and file size
July 29, 2014 10:27 AM   Subscribe

I've got a lot of B-Roll and the file sizes are too much for us to maintain them in a usable way. 300 gb for a 30 min .avi? What are decent formats/compressions that are acceptable but that also give manageable file sizes?

The b-roll is all scenic and ski footage. The total amount isn't too bad, about a terabyte, but many of the files are too big to even share with Dropbox so they just sit on hard drives that don't get used. I can't help but feel some of the older giant files are of lower quality than something 1/100th the size that was generated by my iPad.
posted by furtive to Computers & Internet (12 answers total) 1 user marked this as a favorite
 
300gb, really? WTF? I don't think that can be right - how would you have recorded it, there's no media that stores 300gb for a (consumer grade) camera that I know of?
posted by RustyBrooks at 10:31 AM on July 29, 2014


I think that has to be a typo, given that later the questioner states that total amount is about a terabyte.

Perhaps it would help if the poster explains more about their anticipated future needs for this footage. It may inform the choice of compression algorithm (by clarifying how much loss is permissible.)
posted by Nerd of the North at 10:41 AM on July 29, 2014


It's not a typo. One of my drives has a 290GB 30 minute .avi using the following codec: 10-bit 4:2:2 COmponent YcbCr V210.
posted by furtive at 10:46 AM on July 29, 2014


H.264 in an MP4/M4V container is an excellent modern combo, playable on nearly all modern devices. Bitrates of around 2200-4400kbps should amount to about 1-2GB/hour of video are are very much viewable. Make it 8800kbps if you want more quality. Set your transcoder for maximum quality (and therefor minimum encoding speed), and let the transcode run by itself, no other resource-needy applications running at the same time or allowed to start themselves. Audio codec (MP3, AAC, or AC3-- I would stick with MP3 for universality) should be around 192-256kbps; you're looking at 1.5-2MB/minute of audio for those, which is really peanuts compared to the video filesizes we're talking about.
posted by Sunburnt at 10:46 AM on July 29, 2014


Thanks Sunburnt. So I'd want 8800kbps if I want to keep it broadcast quality?
posted by furtive at 10:49 AM on July 29, 2014


8800 is somewhere on the order of DVD quality for SD (720x480i for NTSC) video-- I think DVDs are around 8000 for a typical 4.3GB DVD, though many DVDs have higher capacity.

If you're okay with 4GB of disk space per hour of video, purely in terms of space and filesize, then compress one of your videos and eyeball the quality; I hate to tell people what the quality is, because the user's eyeball is the best standard. But I think you'll be very happy with the quality, unless your standards are much higher than mind.
posted by Sunburnt at 10:59 AM on July 29, 2014


You would want to know if you the video 720, 1080, or if it's so old that it's SD video. 8000 is ok for 720. If you have 1080, you should go with a higher bitrate, somewhere between 10,000 and 20,000. If it's SD, it's not actually broadcast quality by modern standards.

If you have the space, it's best to default to a higher bitrate.
posted by ohisee at 11:04 AM on July 29, 2014 [1 favorite]


Also, I've heard some places consider 50,000 to be appropriate for broadcast, but it varies, so if you have a particular broadcaster in mind, it's best to check with them on their desired settings. If you just want it to be universally good for a while, use an encoder that will give you an estimate of the file size at different rates and use the highest one you can manage on your system.
posted by ohisee at 11:15 AM on July 29, 2014


Yeah 300GB is definitely not a typo for completely uncompressed video. It's SIMPLY HUGE.

H.264 is a solid choice, though you might also want to consider Apple ProRes. If you ever plan to edit in Final Cut, you'll be converting to that anyway.

I look at video kinda-sorta for a living, and I've never been able to see a difference between uncompressed and compression with a good codec like those above at the maximum quality. I think where you get in trouble is with repeated compressions, or with dropping the quality. One well-done compression is perfectly acceptable for making a "master" you plan to keep for a long time. (Bear in mind a lot of modern cameras, like DSLRs, *shoot* in H264 in the first place, and those are used on professional commercials, tv shows, and even some movies.)
posted by drjimmy11 at 11:49 AM on July 29, 2014


Oh and as always, the free software MPEG Streamclip is your friend. It's the only conversion program or process that has ever had me *not* throwing things and swearing for the neighbors to hear.
posted by drjimmy11 at 11:50 AM on July 29, 2014 [1 favorite]


I can't help but feel some of the older giant files are of lower quality than something 1/100th the size that was generated by my iPad.

Well, it's probably old, right? The camera on an iPad is quite superior to a consumer camcorder from 10 years ago. Just don't expect miracles: Nothing you can do will improve the quality of the source material- it's just about not degrading it too much while getting it to an acceptable size.
posted by drjimmy11 at 11:53 AM on July 29, 2014


Not a professional or anything, just a weird obsessive person. I've played around with this a lot.

50,000 is bluray quality. I mean, it's not, but that is the point of no more returns. Anything compressed at all is going to get macroblocked a little, and that was the point at which everything basically looked like JPGs at quality 100 whenever i paused, and on every frame.

Cable/satellite compression is going to fuck up everything horribly anyways. I mean, i get why you'd want a high quality source file, but i just don't see the purpose of anything higher than that.

I never hunted around much with 720p, but i'd assume that would be somewhere around 25,000 to 30,000, seeing as how it's almost exactly 1mp and 1080p is pretty much 2mp. 8800-10k for SD widescreen should be spot on as well.
posted by emptythought at 12:47 PM on July 29, 2014 [1 favorite]


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