Exporting H.264 from After Effects file for HD Broadcast

[Kevin Camp]

with variable bit rate file size with h.264 can vary quite a bit based on how much information is within a frame and how much changes happens from frame to frame…

30 seconds of black will compress down considerably more than 30 seconds of fast action video…

so it’s possible, and if the settings were the same for both compressions, then i think you’re ok.

also, are you really delivering 1080 at 59.94 fps, or is it 59.94 interlaced?

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW

[Scott Anderson]

Thanks for the feedback. I have the AE composition set for 59.94 fps per station/ftp instructions for hd. When I exported h.264 out of After Effects I wasn’t able to confirm the data rate for the file in QT or Cinema Tools but it did tell me it was 59.94 fps. H.264 out of compressor allowed me to see the data rate in QT after it was finished. I originally was sending Apple 422 with the older SD formats but we’ve converted the spots to hd, so using the h.264 format for broadcast purposes is new for me. The specs provided from the various stations were all over the place. Some only said “hd in h264 format” others added the 59fps. If I have a production contact I drop a call in to confirm. Most have eliminated the need for slate stuff. The file size on this one made me a little nervous. With the higher frame rate, I was sure it would be a large file. I’ll upload the files and verify with the stations that they’re ok. Thanks again.

Scott Anderson

[Scott Anderson]

Thanks. When I noticed the 59.94 fps on a few specs I thought it was for the frame rate for the comp settings. Should I be leaving the comp settings at 29.97 frame rate for 1920×1080 HD? Also, should I be in 8bit or 16 bit? I found the upper field setting to change but I didn’t see anything regarding field rate. Where would I find it to change?

Here’s what I get from the various stations/cable companies –
Interlaced Upper Field First, 29.97 fps, .mpg (mpeg2) 720p 59.94fps 4.2.0, mpg2 format or quicktime, All HD commercials and PSAs must be produced in MPEG2 HD 1080i with a 59.94fps field rate. They must be converted by your production company and uploaded to our FTP site as .mov files using the H.264 codec.

Thanks for the help. My TV days were pre-digital (3qtr, 1inch stuff) and my pre-ftp spots were uncompressed files sent out for beta tapes.

Scott Anderson

[Scott Anderson]

The best one I have is below – otherwise most say just use quicktime or mov file.
The 59.94 fps detail showed up in another market I do work with . Most of the stations there had it in their specs. The one I’ve pasted below was generally what I pasted in or less. Can you tell a good way to verify the data rate after exporting out of AE? I set it for vbr with a low of 35 mbit and a high of 50 mbit but can’t check the final output. When I do h.264 straight out I can’t check the file in Cinema Tools and QT won’t show it at all. Thanks again.

High Definition:
1080i Quick Time MOV:
 1920×1080 resolution
 H.264 compression
 Interlaced Upper Field First, 29.97 fps
 Uncompressed audio, 48 KHz
 16:9 aspect ratio (1.0 pixel aspect ratio)

720p Quick Time MOV:
 1280×720 resolution
 H.264 compression
 Progressive, 29.97 fps
 Uncompressed audio, 48 KHz
 16:9 aspect ratio (1.0 pixel aspect ratio)

Scott Anderson

[Vishesh Arora]

Dave

Kevin works at a TV station, and I used to. That’s why we’re questioning the 59.94 FRAMES per second.

We both know that TV stations don’t broadcast that way: at 1080, they broadcast 59.94 FIELDS per second, and the field order is upper field first.

Yesterday, I created a file to broadcast with specs(given by Client):

HD 1080p
25fps
.h264
.Mov
Bit rate: 20-30 Mbps

How will I get to know whether the client is asking for 25 Frames per sec or 25 Fields per second by looking at these specs?

Also for QuickTime, there is no default preset for 1080p(but there is for 720p). So is it right to assume that its unusual?

Don’t know much on how Broadcasting works. A little explanation will help.

Vishesh Arora
3D and Motion Graphics Artist
Films Rajendra

Blog:
https://digieffects.wordpress.com

2011 3D Demo Reel:
https://www.youtube.com/watch?v=lHPgIJU_BR8

[Scott Anderson]

Thanks Dave. I ended up using 29.97/422 as I had in previous uploads. I’m going to reach out to the production folks on the other end for future specs and clarifications. Some of the info is coming from non-production people so it may be getting a little lost in translation.

Scott Anderson

[Juan Manuel]

Vishesh: roughly speaking, fields are half a frame, containing only either even or odd lines. So for PAL, it means you have, if interlaced, 25 frames per second, which means 50 fields per second – two fields make a complete frame. That, in an interlaced setting. Progressive video doesn’t subdivide frames into fields.
They are asking you progressive material, so that would be, in your case, 25 frames per second, no fields, with a resolution of 1920×1080

[Brian Tario]

I recommend the free Mac app VideoSpec for analyzing the properties of a video file. You’ll get much more info than via QT, VLC, etc.

[Vishesh Arora]

Thanks Dave and Juan.

Vishesh Arora
3D and Motion Graphics Artist
Films Rajendra

Blog:
https://digieffects.wordpress.com

2011 3D Demo Reel:
https://www.youtube.com/watch?v=lHPgIJU_BR8

[Scott Anderson]

Cool. Thanks again. I’m normally a browser here but when I’ve needed help someone always comes through.

Scott Anderson