MP4 encoding results always poor; large files and low quality

David_Coombes wrote on 10/20/2014, 9:42 AM

Although having used Magix for years, encoding a decent quality mp4 video is still a mystery to me. I've just tried several different encodes of a 10 minute film at 720p25. At 3 Mbps VBR, the file comes in at >200 MB in size and exhibits dreadful macro-blocking and banding when played back. This is using the inbuilt MP4 export (Main Concept) in Magix ME Pro 2013+. I've tried constant quality, VBR, CBR, highest quality, and all sorts, to no avail. I've also tried hardware encoding via Intel's QuickSync. In stark contrast, an export in Windows Media format produces excellent results at 75% quality in only 100 MB.

The source material is a few high bitrate video clips and a couple of png stills on two layers,so nothing complicated. Machine is an i7 4770 with 8 GBs RAM and Windows 7 64 bit.

Given the ubiquity of mp4 support at a headware level in devices, it's the format I want to use, but I just can't get the quality right. What's the secret?!

Comments

terrypin wrote on 10/20/2014, 12:39 PM

Hi,

Are you able to upload say a 10 MB extract that exhibits the poor quality, so that we can try it? There are many suitable hosting sites. I use Dropbox.

johnebaker wrote on 10/20/2014, 12:51 PM

. . . . just tried several different encodes of a 10 minute film at 720p25. At 3 Mbps VBR, the file comes in at >200 MB in size and exhibits dreadful macro-blocking and banding when played back. . . . .

I am guessing you used the Flash 1240*720P setting for export - the bitrate, file size and blockiness are consistent with the results you have described.

. . . . a headware level in devices . . . .

Do you mean hardware level?

. . . . What's the secret? . . .

There is always a trade off between filesize and quality for a given resolution of video and what you are aiming for in terms of the end user experience and device coverage ie if you want:-

Small file size?

- you are going to have to lower the video resolution
Streamable from Youtube, Vimeo etc?

- use the recommended file formats/resolutions/bitrates for those sites
Support for as many devices as possible?

- create multiple versions at different device resolutions.

If you want higher quality then you are going to have to up the bitrate to at least 6 - 12Mbps and accept the larger file size.

The above assume you wish to stick to the mp4 format.

HTH

John

rmoore304 wrote on 11/4/2014, 9:30 AM

I'm just going to echo johnebaker: for mp4 you are going to need a higher bitrate at the size you are rendering out to. I have been exporting to NTSC DVD size (720x480) and use 1800 mbps vbr but my videos are board meetings with virtually no movement. I have experimented with footage with more action and notice I have to go up to 4000+ mbps to get a good picture. My settings for static motion meetings are:

720x480 (DVD - NTSC Widescreen)
1800 Mbps
29.97 fps (same as source)
150 GOP
Profile = High
Quality = Good
44.1 K audio
128 Kbps audio

Here a sample of those settings.
http://vimeo.com/103443645

Randy