Video still doubles in size

vinceq60 wrote on 2/6/2008, 11:36 PM
I dont understand. Ive been editing video for 10 years and never experienced this before. I rendered a video as MP4, AVI, MPEG 1, MPEG 2 and wheni import it into VMS8 it doubles in size and sometimes more. The mp4 was 50mb, when i imported it it became 7.4 gigs. The mpeg 2 was 2.8 gig, when i imported it it became 7.8gigs. the mpeg1 was 1.3 gigs when i imported it it became 7.1 gigs, the avi was 1 gig, when i imported it it became 7.3 gigs. There is something wrong here. Ive never ever encountered importing of a video, only to have it double or triple in size. No matter what type or size video i import, it becomes more than 7 gigs. Needless to say I can no longer burn any dvd's. because no matter what size it is before i import it. once it gets into VMS it magicaly grows to over 7 gigs. Anyone ever heard of this befior? why would a file increase in size just by importingit. Please Please help. I cannot burn any videos whatsoever.

Comments

GeorgeW wrote on 2/7/2008, 5:07 AM
It "grows" because for SD DVD, it needs to be made dvd compliant.

mp4, avi, and some mpeg1 (although mpeg1 can be legal for dvd) will need to be re-compressed to mpeg2 for dvd. The mpeg2 file shouldn't "grow" unless it doesn't meet sd-dvd spec, or if you happen to be modifying it someway within DVDA.
Terje wrote on 2/7/2008, 9:49 AM
The DVD standard uses, as was pointed out, MPEG-2 encoding. There is also restrictions on the bitrate etc that is used, both minimum and maximum actually. So, all of your movies that have been rendered to highly compressed formats like MP4, will have to be re-encoded into MPEG-2 at standard DVD bitrates.

Given typical bitrates, a little over two hours worth of video will typically take somewhere around the space you say. 2 hours 10 minutes of video with AC3 audio at 8M/s (standard DVD) is 7.9G worth of video no matter what size your original video was.

To find out what size your video will be on a DVD go to any video site and look up their bitrate calculators, or google bitrate calculator. This will give you what you need. DVDA uses a bitrate calculator internally to do this. If you import a 2 hour MP4 it doesn't actually change it's size until you start the prepare/burn process, but it calculates what the size will be based on the length (time) of your movie, not the size of the original.

You also should never encode to MP4 or other highly compressed formats (DivX) and import these into DVDA, the re-encode into MPEG-2 will probably make your movie look terrible.
vinceq60 wrote on 2/11/2008, 8:56 AM
I understand. I did something to change the settings and I dont know what. I burn 4 or 5 dvds a week, and its never done this before. Any clue as to what i may have accidentaly done in the settings to change it? Thanks for the help guys.
MPM wrote on 2/13/2008, 3:47 PM
FWIW there's a chance I imagine that DVDA is having some problems translating (or rather trans-coding) from your video source files... there can be a huge variance between mp4 files for example, and DVDA may not handle all of them gracefully. If that was the case, perhaps one of the many, free-ware, transcoding programs at videohelp.com might be useful or at least easier? Many of them have pretty decent flexibility when it comes to input formats. If you did try something like this you'd just import your finished mpg2 into DVDA.

As far as DVDA goes, depending on version you might be able to set the default bit rate in preferences, the project bit rate in the File Menu -> Optimize dialog, & the video file bit rate thru the properties menu on the upper right. Normally you're probably looking at something between 8 & 5 for average bit rate, for about 1.5 - 2 hours worth of video -- the higher the bit rate the better it looks but the bigger the file.

When it comes to importing mpg2 files it's a bit different. DVDA will normally import any DVD spec mpg2 fairly well. Looking in the Optimize window will tell you whether DVDA plans on re-encoding the file or not. When it doesn't import mpg2 correctly the fault could be the way the file's written, or that it doesn't fit within the parameters that DVDA thinks it should use (check the preferences mentioned above). If the reported bit-rate is too high, a program like DVD Patcher can change just the 1st header and hopefully DVDA will now like it fine. DVDA also likes mpg2 a bit better if it's muxed, but without an audio file (TMPGEnc works well). If the mpg2 itself has problems, ProjectX might help, allowing you to re-write the file without re-encoding, changing flags etc. along the way.