Andy,

Knowledge source: http://forum.cyberlink.com/forum/bookmarks/list/4556.page

Mp4 Tweaking: http://forum.cyberlink.com/forum/posts/list/17939.page

Andy,

if I'm not completely out of it:
when you are in "produce":









OR, follow Dafydd's tweaking-recipe,
not so scary as it may seem.

Nina


Just something.
https://www.petitpoisvideo.com

Thanks Nina and Dafydd,

I went into the Profiles.ini file and was able to dramatically reduce my video file sizes. What was quite interesting was how I was able to go from a file size of 41 MB (6,000 kbps) to 7.67 MB (1,000 kbps) and the quality of the playback was pretty much the same.

With this "getting it" about bitrates, another question came up. Here it is.

If the resolution setting in the profile is staying the same, in this case it's 1280 by 720, but the total file size is being reduced by reducing the bitrate, where is the reduction coming from?

In other words, if the number of pixels is staying the same, where is the reduction in data coming from?

Thanks for all the help,

- Andy

Andy,

In my words and my take:
The bitrate in the template is the instruction which controls the quality/compression/render of the codec used to produce the video. By altering the level and staying within the "engines" range you can successfully create a rendered file. By going "outside" the parameters of the default settings we are going into "no-mans-land" and risking possible acceptance problems. However you'll find variations in bitrate and frame size (which is what 1280x720 is) will affect the finished file size (mbs) - smaller but excellent quality. You must however think of what you're aiming for. An editor should aim to maintain the level of the edited file until the time comes for the finished file to be produced for a variety of purposes.

I've waffled... and will need to edit this post a bit.

Dafydd,

I'm getting what you are saying. But would like to hear more.

It seems as though what you are saying is the bitrate parameter does quite a number of things all together to bring the total file size down.

Feel free to elaborate!

:

- Andy

bitrate effects how much change is encoded from frame to frame, if your video has only a little change for a number af frames, the algorithm needs very little data to encode the change. for sports and complicated scenes with lots of motion, you need a higher amount of data for each frame. if variable bit rate option, then algorithm will adjust, if you only allow it a fixed bit rate, then it will compromise, high motion scenes will be blocky and really look bad. RTX 2060 SUPER 8GB GDDR6
(2 NVME 2TB, 1 SSD 2TB, 3SATA 18TB )
PD18 ULTIMATE 64bit
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Basically an uncompressed video size would be
(frame height x frame width) x (color format) x (frames/sec) x (seconds) = uncompressed video size (bits)

(frame height x frame width) is the total pixel count
color format depends on video format YUY2 and UYVY have 16 bits/pixel and RGB24 has 24 bits/pixel
The first 3 multipled terms above is the video bitrate, bits/sec or divide by 8bits/byte to get the more traditional user file size reference.

The codec basicly divides the uncompressed video size by some factor based on how good the compression logic of the codec. All codes are different on what they can do. A very good codec has massive compression to reduce file size with limit quality loss, but then during playback the playing utility needs to uncompress the video stream too, this can require significant horsepower on playing device. That's one of the reasons HD is rather demanding on systems and PD coughs it up on lightweight PC's.

Maybe that helps you some on what controls video size and quality.

Jeff

if you only allow it a fixed bit rate, then it will compromise, high motion scenes will be blocky and really look bad.

Just for completeness, this may be true if the bit rate set is too low for the scene, if the CBR is set high enough, limited degradation will occur but, of course, the static scenes will result in overly large amounts of data being encoded. As usual a compromise bit rate is usually the best option.

The advantage of the modern "intelligent" (my term) codecs is that they may "constantly" (my term) adjust the algorithm to suit the content to arrive at the optimum quality/size ratio.

http://msdn.microsoft.com/en-us/library/dd757004.aspx
http://msdn.microsoft.com/en-us/library/dd743964.aspx

Cheers
Adrian Life is really simple, but we insist on making it complicated. (see below)
Confucius
AMD Phenom IIX6 1055T, win10, 5 internal drives, 7 usb drives, struggling power supply.