Why is my MP4 much bigger than my WMV !?

[Bansaw]

I am converting a WMV file to an MP4 file using Sony Vegas 11.0.
What I can't understand is why I am getting a filesize which is much higher than the WMV and the destination frame size is even smaller ! ? Its a mystery.

Any help greatly appreciated.

(If I make them the same bit rate, the MP4 looks bad. how can WMV produce better looking files for the filesize?)


WMV File original details:
General
Format : Windows Media
File size : 14.2 MiB
Duration : 6mn 42s
Overall bit rate mode : Variable
Overall bit rate : 297 Kbps
Maximum Overall bit rate : 769 Kbps
Video
ID : 2
Format : WVP2
Codec ID : WVP2
Description of the codec : Windows Media Video 9.1 Image
Duration : 6mn 42s
Bit rate mode : Variable
Bit rate : 15.5 Kbps
Width : 1 024 pixels
Height : 768 pixels
Display aspect ratio : 4:3
Frame rate : 30.000 fps
Bit depth : 8 bits
Bits/(Pixel*Frame) : 0.001
Stream size : 760 KiB (5%)
Language : English (US)


MP4 file destination (note that its 640x480)!
General
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42
File size : 54.6 MiB
Duration : 6mn 41s
Overall bit rate : 1 141 Kbps
Encoded date : UTC 2016-01-29 19:47:32
Tagged date : UTC 2016-01-29 19:47:32
Video
ID : 2
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L3.0
Format settings, CABAC : Yes
Format settings, ReFrames : 5 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 6mn 41s
Bit rate mode : Variable
Bit rate : 945 Kbps
Width : 640 pixels
Height : 480 pixels
Display aspect ratio : 4:3
Frame rate mode : Constant
Frame rate : 30.000 fps
Standard : NTSC
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.103
Stream size : 45.2 MiB (83%)
Language : English
Encoded date : UTC 2016-01-29 19:47:32
Tagged date : UTC 2016-01-29 19:47:32

[DB83]

No mystery.

Frame size is irrelevant.

File size = length * bitrate. The .mp4 bitrate is much larger than the .wmv so the final size is much bigger.

[Bansaw]

No mystery.

Frame size is irrelevant.

File size = length * bitrate. The .mp4 bitrate is much larger than the .wmv so the final size is much bigger.

Thanks, I actually just added this text to my original post:
(If I make them the same bit rate, the MP4 looks bad. how can WMV produce better looking files for the filesize?)

Surely WMV isnt better bang for the buck than MP4? If I make the bit rate equal, then the MP4 looks very pixilated and looks poor.

[PuzZLeR]

No mystery.

Frame size is irrelevant.

File size = length * bitrate. The .mp4 bitrate is much larger than the .wmv so the final size is much bigger.

Thanks, I actually just added this text to my original post:
(If I make them the same bit rate, the MP4 looks bad. how can WMV produce better looking files for the filesize?)

Surely WMV isnt better bang for the buck than MP4? If I make the bit rate equal, then the MP4 looks very pixilated and looks poor.

You can encode it 10x bigger in file size, and the MP4 will not look any better. It will only be as good as near-identical to the source, the WMV in this case, or worse - no matter how much bitrate you apply.

Even if you do it the other way MP4-> WMV, same thing. It doesn't imply one is better than the other.

And MP4 is a container. It's what's inside that counts, the AVC, or H.264, video, which is arguably better than WMV in compression, but again, H.264 is not magic - the best quality it will ever give you is something that looks like the source.

A true test between the two would be using the same Source, and comparing: Source->WMV vs Source->H.264, at the same bitrate and rather similar settings. (Not from each other when one is the source. Not fair.)

And, by the way, I also think Vegas'es H.264 encoder may suck, not that WMV is superior. (But I don't use Vegas, so this is only a haphazard assumption.) There are better H.264 encoders. I personally use editors for editing, not encoding the result, which would be a different science.

[DB83]

And the problem with the original is that the bitrate is small with a large frame size.

You will never match that with another format/container/codec and certainly not at that bitrate.

[Bansaw]

And, by the way, I also think Vegas'es H.264 encoder may suck, not that WMV is superior. (But I don't use Vegas, so this is only a haphazard assumption.) There are better H.264 encoders. I personally use editors for editing, not encoding the result, which would be a different science.

Yes, Vegas may have a poor encoder. I have used Apple Compressor for MP4's and its done a much better job (altough it wont take WMVs for this job).
I understand what you're saying about the MP4 not being able to achieve a better look because it won't be better than the source, but the MP4 is way, way worse than the original WMV, not just slightly worse.

[Tom Saurus]

Bansaw: A couple good free tools to add to your computer are Vidcoder and Video To Video Converter. Hopefully Vidcoder will accept your WMV as an input. You can make your own presets in Vidcoder and experiment to find one that is just right. It is a terrific tool and I am sure there are people here that will give you advice on how to get the most out of it.

[DB83]

The problem is that any encode must interpret the frame it receives.

Another illustration is to take a low bitrate mpeg2 (Dvd) and up-convert that. The encoder sees the pixels but can not remove the pixelation that will be present playing back that original file on a large tv screen.


The original is not very large so might I suggest that you upload it here as an attachment. So rather then randomly suggesting an encoder others can try and see if it can be improved upon.

[PuzZLeR]

And, by the way, I also think Vegas'es H.264 encoder may suck, not that WMV is superior. (But I don't use Vegas, so this is only a haphazard assumption.) There are better H.264 encoders. I personally use editors for editing, not encoding the result, which would be a different science.

Yes, Vegas may have a poor encoder. I have used Apple Compressor for MP4's and its done a much better job (altough it wont take WMVs for this job).
I understand what you're saying about the MP4 not being able to achieve a better look because it won't be better than the source, but the MP4 is way, way worse than the original WMV, not just slightly worse.

Like I said before, I do believe the encoder under the hood of Vegas isn't a very good one, or the settings you're using with Vegas aren't the best. If the H.264 video is significantly worse under those conditions, then you need to investigate other options.

Good practice preached by many here will say that for best results use different tools best suited for different tasks instead of one-for-all. In this case, I still say an editor is an editor. I never let my editors do anything more than edit. Any other abilities they have are token convenience additions, not necessarily very good abilities.

I classify a built-in encoder as a convenience offering when it's a feature on an editor. I say use another tool to encode once you output from Vegas. However, is there any way you can smart render your WMV from Vegas, or, at least output it as lossless? If so, you should be on your way to better quality with the resulting MP4.

[jagabo]

I suspect the video is basically a slideshow and the WVP2 video isn't really 30 fps. That's why it's bitrate is so low, only 15 Kbps. Vegas' AVC encoder probably isn't smart enough to allocate bitrate efficiently at such low rates.

[PuzZLeR]

I suspect the video is basically a slideshow and the WVP2 video isn't really 30 fps. That's why it's bitrate is so low, only 15 Kbps. Vegas' AVC encoder probably isn't smart enough to allocate bitrate efficiently at such low rates.

Well, if it's a slideshow, I would also think Vegas'es AVC encoder isn't smart enough to handle the more visible (and hideous) "GOP pulsing" or "GOP shimmers" that could result in the encoding of such content. If this is the case, no wonder it would look horrible.

I would try x264 and --open-gop normal (or --open-gop bluray if for blu-ray) to alleviate such a problem.