Why is my MP4 bigger in size than the WMV !!??

Bansaw2 wrote on 1/29/2016, 1:48 PM
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.



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

Comments

silvertone1938 wrote on 1/29/2016, 3:25 PM
WMV Overall bit rate: 297 Kbps
MP4 Overall bit rate: 1,141 Kbps

Same file length * Four times higher bit rate = Four times larger output file

This is the entire answer. If you'd like a lower file size for the same video length, lower the bit rate. Nothing else is directly involved in file size.

FWIW, you can almost definitely get away with a MUCH lower bit rate than 1.2 Mbps for a 640x480 MP4 file.
musicvid10 wrote on 1/29/2016, 4:16 PM
297 kbps
Hehe
MSmart wrote on 1/30/2016, 10:29 AM
54.6MB
Hehe
TreeTops wrote on 1/30/2016, 11:10 AM
The OP has asked this same question on another forum and has received some good answers.
vkmast wrote on 1/30/2016, 11:22 AM
Those answers are here, JFY.
MSmart wrote on 1/30/2016, 1:40 PM
Just for your......... what?

Don't leave me hanging vk.
vkmast wrote on 1/30/2016, 2:03 PM
Judge for yourselves;)
MSmart wrote on 1/30/2016, 2:11 PM
Oh, that JFY. Doh!
musicvid10 wrote on 1/30/2016, 6:19 PM
Suggest you try Handbrake mp4.
Much better at low bitrates than Mainconcept.