HUGE AVI file sizes at DVinfo.net

Richard Browne · April 5th, 2006, 09:23 AM

I am a true neophyte, so don't presume I know what most of you know.

I downloaded about 2 hours of DV tape using Sony Vegas Movie Studio (version 6). It created a bunch of clips, but the totality of the clips was about 35 Gb! Is this normal?? Is there a reasonable alternative, especially if I plan to edit to make a home movie? My bigger concern is being able to archive these AVI files, so that I need not worry about the tape or camcorder not working some day. Is there compression software that would shrink the files without substantial loss of content?

Anything you could do to help would be ... helpful (from "Monty Python and the Holy Grail).

Richard Browne
Dallas, TX

Matthew Nayman · April 5th, 2006, 10:21 AM

That seems about right. You have a few choices for archiving...

You keep tapes.
You can export raw files as Mpeg 2 on DVD
You can get some external HD's and keep files on those (250gb for about $200, I have a few).
Or you can do what I do, just keep adding storage in your comp. I have abour 1 terabyte of space, using about half.

Hey, DV is huge... Imagine HD

Emre Safak · April 5th, 2006, 10:37 AM

Like Matt said, it is normal. These AVI files are uncompressed (as your camcorder allows, that is). Typically you archive them back onto tape. DVD+Rs are affordable option, too (and more convenient). For normal viewing you can make a DVD or render an MPEG-4 file (say, Quicktime).

Edward Troxel · April 5th, 2006, 08:10 PM

#1) 2 hours of DV-AVI should be about 26Gig

#2) DV-AVI is NOT uncompressed.

Emre Safak · April 5th, 2006, 08:38 PM

They are a chroma subsampled, but they are not otherwise compressed.

[edit: ...or so I thought. DV uses DCT intraframe compression, so I am wrong.]

Jack Smith · April 5th, 2006, 10:46 PM

As Edward said DV avi is NOT uncompressed.
Raw YUV video is around 30 MB/sec and DV is less than 4MB/sec.
Ergo the codecs that DV uses such as Mainconcept ,Microsoft ,etc.
And again Edward is correct 2 hours of DV in a single file would be about 26GB
However ,when broke into a number of small files the total size will exceed the 26GB by quite a bit sometimes.One reason for this is the file size is rounded up to the nearest file size parameter depending on how you have your computer set up.
That's why if you check the properties of a file it will say something to the effect of....... SIZE: (8,482,816)bytes 8,486,912 bytes used.

Alex Thames · April 11th, 2006, 12:12 AM

I asked a similar question once before, but didn't really understand all the technical answers I got. How does one compress the large 13gb/hour DV-AVI file into something much smaller without much loss of quality? I gather Virtual Dub might be able to do this, or compression can take place within Vegas directly when you choose Render As, but what is the step-by-step to achieve a good compression? Such as turning a 26gb .avi file down into something closer to 1gb.

Patrick King · April 12th, 2006, 10:35 AM

Alex,
When you are asking how to compress a 13GB AVI to a file of about 1GB, you are talking about rendering. I don't know of a single method of compressing AVIs that much that would be considered lossless. A 13GB DV-AVI is almost exactly one hour of video and even compressing pretty harshly with MPEG2, you'll probably be above 1GB.

Some of the mp4 codecs compress to smaller file sizes, but currently that limits you to playback on a computer (or PSP). Set-top TV playback is generally through DVDs which are MPEG2.

Seth Bloombaum · April 12th, 2006, 12:57 PM

Patrick is right. Further...

You can get the size smaller using delivery formats such as MP4, WMV, etc.

But these are considered delivery formats for good reason. If you later want to re-edit somthing that now exists only as a heavily compressed file results will be far worse than if re-edited from your 13GB/hr DV-AVI file.

However, perhaps you go back to your original DV tapes on the shelf, which are a pretty inexpensive way to store 13GB/tape.

In selecting a delivery format the question is "how will it be watched", that is, with what equipment, and how will the video be transported there. So, compressing for casual hard drive use is quite different than sending something to a friend in China, which is different than via internet... DVD... you get the idea.

Guy Bruner · April 12th, 2006, 01:11 PM

Alex,
Robert Heinlein once said "TANSTAAFL" (there ain't no such thing as a free lunch). If you want smaller files, you have to throw away content which reduces quality. The Holy Grail of compression right now is to get the smallest files possible while maintaining the maximum quality possible. The current H.264 or AVC codec is about as compressed as you can get while maintaining quality. Even then, you are going to have to select a higher bitrate to keep the quality.

DV is compressed 500% and has a bitrate of 25 Mbps. Standard definition MPEG2 for DVD has a max bitrate of 9.8 Mbps (ok, there's some slop in here but you have to allow for the audio stream). MPEG2 at this bitrate is nearly as good as DV but there is some degradation, especially when motion is involved. H.264 is about 5 Mbps for quality similar to MPEG2 at 9.8 Mbps. For file sizes based on time, multiply the bitrate by 3600 to get the size of a 1-hour file. The bottom line is a 1-hour, 5 Mbps H.264 file will still be 2.25 GB. While this is much smaller than a 13 GB DV file, the quality is less and it is extremely hard to edit.

April 5th, 2006, 08:10 PM	#4
Edward Troxel Sponsor: JET DV Join Date: Dec 2001 Location: Southern Illinois Posts: 7,953	#1) 2 hours of DV-AVI should be about 26Gig #2) DV-AVI is NOT uncompressed. __________________ Edward Troxel [SCVU] JETDV Scripts/Scripting Tutorials/Excalibur/Montage Magic/Newsletters

April 5th, 2006, 08:38 PM	#5
Emre Safak Trustee Join Date: Feb 2004 Location: Brookline, MA Posts: 1,447	They are a chroma subsampled, but they are not otherwise compressed. [edit: ...or so I thought. DV uses DCT intraframe compression, so I am wrong.] Last edited by Emre Safak; April 6th, 2006 at 07:17 AM.

April 12th, 2006, 10:35 AM	#8
Patrick King Major Player Join Date: Jul 2004 Location: Enterprise, AL Posts: 857	Alex, When you are asking how to compress a 13GB AVI to a file of about 1GB, you are talking about rendering. I don't know of a single method of compressing AVIs that much that would be considered lossless. A 13GB DV-AVI is almost exactly one hour of video and even compressing pretty harshly with MPEG2, you'll probably be above 1GB. Some of the mp4 codecs compress to smaller file sizes, but currently that limits you to playback on a computer (or PSP). Set-top TV playback is generally through DVDs which are MPEG2. __________________ Fear No Weevil!

April 5th, 2006, 09:23 AM	#1
Richard Browne Tourist Join Date: Apr 2006 Location: Dallas, TX Posts: 1	HUGE AVI file sizes I am a true neophyte, so don't presume I know what most of you know. I downloaded about 2 hours of DV tape using Sony Vegas Movie Studio (version 6). It created a bunch of clips, but the totality of the clips was about 35 Gb! Is this normal?? Is there a reasonable alternative, especially if I plan to edit to make a home movie? My bigger concern is being able to archive these AVI files, so that I need not worry about the tape or camcorder not working some day. Is there compression software that would shrink the files without substantial loss of content? Anything you could do to help would be ... helpful (from "Monty Python and the Holy Grail). Richard Browne Dallas, TX

April 5th, 2006, 10:21 AM	#2
Matthew Nayman Major Player Join Date: Feb 2005 Location: Toronto Posts: 917	That seems about right. You have a few choices for archiving... You keep tapes. You can export raw files as Mpeg 2 on DVD You can get some external HD's and keep files on those (250gb for about $200, I have a few). Or you can do what I do, just keep adding storage in your comp. I have abour 1 terabyte of space, using about half. Hey, DV is huge... Imagine HD

April 5th, 2006, 10:37 AM	#3
Emre Safak Trustee Join Date: Feb 2004 Location: Brookline, MA Posts: 1,447	Like Matt said, it is normal. These AVI files are uncompressed (as your camcorder allows, that is). Typically you archive them back onto tape. DVD+Rs are affordable option, too (and more convenient). For normal viewing you can make a DVD or render an MPEG-4 file (say, Quicktime).

April 5th, 2006, 10:46 PM	#6
Jack Smith Major Player Join Date: Nov 2003 Location: ontario Posts: 445	As Edward said DV avi is NOT uncompressed. Raw YUV video is around 30 MB/sec and DV is less than 4MB/sec. Ergo the codecs that DV uses such as Mainconcept ,Microsoft ,etc. And again Edward is correct 2 hours of DV in a single file would be about 26GB However ,when broke into a number of small files the total size will exceed the 26GB by quite a bit sometimes.One reason for this is the file size is rounded up to the nearest file size parameter depending on how you have your computer set up. That's why if you check the properties of a file it will say something to the effect of....... SIZE: (8,482,816)bytes 8,486,912 bytes used.

April 11th, 2006, 12:12 AM	#7
Alex Thames Major Player Join Date: Feb 2006 Location: New York Posts: 508	I asked a similar question once before, but didn't really understand all the technical answers I got. How does one compress the large 13gb/hour DV-AVI file into something much smaller without much loss of quality? I gather Virtual Dub might be able to do this, or compression can take place within Vegas directly when you choose Render As, but what is the step-by-step to achieve a good compression? Such as turning a 26gb .avi file down into something closer to 1gb.

April 12th, 2006, 12:57 PM	#9
Seth Bloombaum Inner Circle Join Date: Sep 2003 Location: Portland, Oregon Posts: 3,420	Patrick is right. Further... You can get the size smaller using delivery formats such as MP4, WMV, etc. But these are considered delivery formats for good reason. If you later want to re-edit somthing that now exists only as a heavily compressed file results will be far worse than if re-edited from your 13GB/hr DV-AVI file. However, perhaps you go back to your original DV tapes on the shelf, which are a pretty inexpensive way to store 13GB/tape. In selecting a delivery format the question is "how will it be watched", that is, with what equipment, and how will the video be transported there. So, compressing for casual hard drive use is quite different than sending something to a friend in China, which is different than via internet... DVD... you get the idea.

April 12th, 2006, 01:11 PM	#10
Guy Bruner Major Player Join Date: Nov 2003 Location: Ashford, AL Posts: 937	Alex, Robert Heinlein once said "TANSTAAFL" (there ain't no such thing as a free lunch). If you want smaller files, you have to throw away content which reduces quality. The Holy Grail of compression right now is to get the smallest files possible while maintaining the maximum quality possible. The current H.264 or AVC codec is about as compressed as you can get while maintaining quality. Even then, you are going to have to select a higher bitrate to keep the quality. DV is compressed 500% and has a bitrate of 25 Mbps. Standard definition MPEG2 for DVD has a max bitrate of 9.8 Mbps (ok, there's some slop in here but you have to allow for the audio stream). MPEG2 at this bitrate is nearly as good as DV but there is some degradation, especially when motion is involved. H.264 is about 5 Mbps for quality similar to MPEG2 at 9.8 Mbps. For file sizes based on time, multiply the bitrate by 3600 to get the size of a 1-hour file. The bottom line is a 1-hour, 5 Mbps H.264 file will still be 2.25 GB. While this is much smaller than a 13 GB DV file, the quality is less and it is extremely hard to edit.