You nailed it John, that's a lot of great information in a five min video. As a recent grad of IPVM U I actually found it was a nice quick review. Thanks.
John, about the apple video. Compression value 90 gives a better picture than compression value 5? I think it's opposite.
One question doesn't the slide of the apple showing res/comp have the compression numbers reversed, (as well as the audio stream)?
On all cameras i can remember, but specifically say Axis, the HIGHER compression number means LOWER quality...
I always thought it was a rough percentage of how much information was lost...
Pekka, Chris, good eye. The numerical scales for compression can be very confusing as manufacturers use both - high numbers mean high compression sometimes and other times high numbers mean low compression.
We have updated the slide in the video to say 'low' or 'high' to make it easier to understand the concept.
Indeed, the best way to truly understand how much compression is being used with H.264 is to use a stream analyzer and discover the actual quantization level selected. This allows comparing across manufacturers.
For those who care about video quality, I highly recommend our How to Measure Compression Tutorial that explains this in depth.
IPVMU Certified | 10/01/13 02:38pm
These are great tips for everyone to reveiw. I have never completely understood the F-stop but I do now.