Compression Techniques Forum
Elephant's Dream question for Ben
Elephant's Dream question for Ben
by epontius on Jul 28, 2007 at 6:24:21 pm

I've just started to follow some of Ben's compression tutorials on the blog using Elephant's Dream and the WMV PowerToy.
I actually downloaded the entire 21GB tar file of 1920x1080 PNGs to have a little more control and quality (and just for the heck of it). As well as the 6 FLAC files, from which I have made a multichannel WAV and a AC3 file from.
However, I can't find information on what the actual frame rate of the PNG sequence should be (24p, 23.976, 29.97?). In one post Ben is using 24p in another it's using 23.976.
I'd like to get the frame rate to match what the film was actually done at so that the audio doesn't drift out of sync.


Re: Elephant's Dream question for Ben
by Ben Waggoner on Jul 31, 2007 at 9:13:22 pm

The PNG sequence should be 24.000 fps.

Which version did I encode at 23.976? That was probably just sloppiness on my part.

My compression blog:

My compression class at Stanford:

Re: Elephant's Dream question for Ben
by epontius on Jul 31, 2007 at 10:57:26 pm

The encoding for Zune. The screen shots of the PRX all show 23.976. I just re-read it and noticed that the text you had 24p...

In any event, it looked fine...I don't have a Zune so it was just an exercise in setting up the encode.

I ended up creating the sequence in AE at 24p and exporting it out using the Huffyuv codec to a AVI to use with media encoder.
I created a multi-channel wav with Adobe Audition and an AC3 file with an old Mac of mine with A pack (I think that's what its called).
I did a couple of your examples with the AVI and multi-channel wav. Which turned out fine...though the WMcmd script example took forever.
I also encoded the uncompressed AVI to MPEG2, built a DVD using the MPEG2 and Ac3 file in encore. Played it back up converted to 1080p via my BD player...looked fantastic.
Guess I was bored last week.

I'd like to see more examples of when to use various settings in the WM Powertoy... You do a good job of explaining the function, it's just more difficult for me to determine when to use it and what to set it at depending on the source material. Such as when to use Adaptive deadzone and overlap and when not to.
Thanks again for sharing your knowledge...