WMV Same Settings - Wildly Different File Sizes

MarcusAur wrote on 5/5/2015, 1:26 AM
Hello,

I have a question about something that has been puzzling me. I have processed two videos to WMV using Movie Studio Platinum 13. The initial videos were recorded using identical settings, and are roughly equivalent in length (about 22 minutes). They are 1080p 30fps videos. Both were processed with *exactly* the same settings in MSP13. Identical. WMV, variable BR at 79% quality. Audio identical. One came out at 400MB, the other came out 1.14GB, over double the size. I look at the file details, and the big one has a bitrate of about 31,000kbps, while the smaller one is about 21,000kbps. So that's different, but still not more than *double*.

Similar situation, only this time the files were recorded using different codecs, but again, main settings (1080p 30fps) the same, and again processed identically in MSP13, and this time the result is even weirder. One is 1.84GB, while the other is 938MB. The 938 MB file is longer - 28 min, while the 1.84GB is 23 min. So I figured the bitrates would be different, and they were. But here's the crazy part. The longer file with the smaller filesize had a *higher* bitrate (35,000), while the shorter file with the larger filesize had a *lower* bitrate (30,500). Since filesize is bitrate x length, how is this possible? Again all settings in MSP13 were exactly the same.

I feel if I can figure out why this is I can make higher quality videos at lower file sizes.

Thank you!

Comments

musicvid10 wrote on 5/5/2015, 10:06 AM
The only way to compare videos encoded with the """"same"""" settings is to see the complete file properties for each using MediaInfo.

What we find 100% of the time is that the file parameters are """"not"""" the same, despite the user's best intentions. You've already suggested that your settings and/or source are not identical, so it's a case of apples and oranges, and MediaInfo will help us pin down the differences.

Going forward, keep in mind that there are only TWO THINGS that affect file size -- LENGTH and BITRATE. Nothing else, and no alchemy involved.

MarcusAur wrote on 5/5/2015, 12:56 PM
Thank you for responding. When I say identical what I mean is that my process is identical, and all the settings I can effect are identical. I cannot speak for the program changing things on its own "under the hood" so to speak, but since I have saved my custom settings I know for a fact that both videos were processed the same way.

In my initial post I gave an example where your statement is patently false. I have a longer video that windows tells me is at a higher bitrate, and yet it's a much smaller filesize that a shorter video that windows tells me has a lower bitrate. So either windows is lying to me or there is something else going on.

Video 1: 1.84GB - 23:25 - 30352kbps data rate - 30544kbps total bitrate.
Video 2: 938MB - 27:52 - 34834kbps data rate - 35026kbps total bitrate.
This is from windows, right clicking the files, selecting properties, and then clicking the "details" tab.

Also, I notice you tend to respond to a lot of people's questions, so I just want to say thank you because you are obviously helping a lot of people on this board and I don't think you work for Sony so you're volunteering. As someone who frequently asks questions all over the place but rarely is in a position to answer them I very much appreciate the work and knowledge people like you put in.
musicvid10 wrote on 5/5/2015, 2:49 PM
Multiple audio tracks?
No way to know without full MEDIAINFO.
That's something you download from Sourceforge.
MSmart wrote on 5/5/2015, 7:52 PM
To add to the request for MediaInfo results, use the Text view and paste them here. It would be helpful for both the input and rendered videos.

You said you used VBR...... if there is more action in one of the videos than the other, then a higher overall bitrate will be used to a larger file, even if it's shorter.