Compressor Output Settings

[Rob Grauert]

Are you trying to compress for the web or are you just trying to have a nice looking H.264 file?

Also, setting a key frame every 1 frame is not a good idea if you plan on restricting the data rate. You will end up creating low quality key frames to maintain your restricted data rate. Try setting a keyframe every 300 frames, or 150 if that does not work

Rob Grauert, Jr.
http://www.robgrauert.com
command-r.tumblr.com

[Sky Soleil]

Hi Rob,

Thanks so much for your reply. I did try the key frame rate at 1 and you’re right it wasn’t a good looking file.

To answer your question: I’m creating high quality digital H.264 files of my live action short film to sell through my website. The files will be purchased, downloaded and then viewed on the buyers PC, Mac or Mobile device.

My goal is to offer the highest quality file with the lowest file size.

Looked on iTunes and found a film with a run time of 14 minutes,same as my film, with a resolution of 720p and a file size of 419.6 MB. Total bit rate was 4099. The picture looks great.

Based on that, I set my file size targets as…

For a 1080p file – 1 to 1.5GB

For a 720p file – 400MB to 600MB

For a 480p file – 200MB to 300MB

—————

Is it reasonable to assume that I can get the quality I saw on iTunes, with the desired file size, using compressor?

They are offering feature length films at 720p that have file sizes of 3GB that look amazing.

Just trying to emulate that. Great quality files with low sizes.

My film was shot on super 16 film and transfered to digital.
My FCP project file sequence settings are 1920×1080 HDTV 1080i (16:9)
Pixel Aspect Ratio: Square
Editing Timebase: 23.98
Uncompressed 10-bit 4:2:2
Quality 100%

Audio 48 kHz
Depth 24-Bit
Config: Channel Grouped

For 1080 in compressor I’ve done tests with the key frame rate set to automatic with a data rate restricted to 15000 and that seems to yield the best results. I ran a test with key frames set to 150 and a data rate restricted to 15000 and that gave me some digital noise in my outdoor shots. Minor but noticeable.

3 Questions:

1. How should I continue to test? Is it just a matter of changing frame rates and data rates? Are there other things I can do to get better quality while maintaining a decent file size?

2. I noticed in my FCP sequence settings my Pixel Aspect Ratio was set to Square. If my aspect ratio is HDTV 1080i (16:9) shouldn’t my Pixel aspect ratio be something else?

3. In Compressor when you’re choosing your Aspect Ratio it gives you the pixel aspect ratio option as well. What should I choose in compression? I’m thinking it shouldn’t be square in either my FCP sequence or compressor.

Thanks for your help.

Sky

Thanks,

Sky

[Rob Grauert]

“Is it reasonable to assume that I can get the quality I saw on iTunes, with the desired file size, using compressor?”

Sure, it will just require some trial and error.

“1. How should I continue to test? Is it just a matter of changing frame rates and data rates? Are there other things I can do to get better quality while maintaining a decent file size?”

The only time I’ve restricted data rate is when I’m loading a video to my personal website. Any other time I use the “Quality” slider. And I always set my Key Frames to Automatic, unless Automatic doesn’t work for some reason (but it always has)

Also be sure you are compressing your audio as well. If you don’t, it will hog up much of the bandwidth. You should go with AAC codec. If you’re stereo mix has the same audio coming out of both speakers, go with mono at 64kbts per second. If you insist on stereo, go with 128kbits per second.

“2. I noticed in my FCP sequence settings my Pixel Aspect Ratio was set to Square. If my aspect ratio is HDTV 1080i (16:9) shouldn’t my Pixel aspect ratio be something else?”

No. square is the correct pixel aspect ratio. Your compressed video should have a square pixel aspect ratio as well. Have you made sure that it does?

“3. In Compressor when you’re choosing your Aspect Ratio it gives you the pixel aspect ratio option as well. What should I choose in compression? I’m thinking it shouldn’t be square in either my FCP sequence or compressor.”

No, for what you are doing, it should be square. Full-raster HD uses square pixels, that is why you’re FCP sequence is set for that. Computer screen and mobile devices also use square pixels, which is why you’re outputting for that. So you’re good to go!

Compression is trick at first for everyone. If H.264 isn’t working for you, try .mp4 compression. Also, for your 720p and 480p encodes, be sure to go into Frame Controls and set the Resize setting to Best.

Also, here’s a tutorial I made for web compression. I don’t remember if it covers exactly what you’re looking for, but its worth a look I think

https://www.youtube.com/watch?v=uTUsA7Em1Ug

Rob Grauert, Jr.
http://www.robgrauert.com
command-r.tumblr.com