Applies to
- SX series video servers
Answer
Creating h.264 files can be a tedious process because of the number of variables that can be adjusted. Â In this guide, we will discuss the implications of and best settings for some of these variables. Â Broadly speaking, the remaining variables can be left with their default values.
Required Settings
These settings MUST be set to the specified values, or the h.264 file will fail Cablecast's file validation process.
Setting Name | Required Value | Notes |
File Extension | .mp4 or .mov | Â |
Profile | Main or High | Â |
Video Codec | h.264 | Â |
Video Resolution |
must match one of the server's supported resolution |
see compatible resolutions tables below |
Video Frame Rate |
must match one of the server's supported resolution |
see compatible resolutions tables below |
 |
Must be constant frame rate |
files with variable frame rates may not play correctly and may be rejected by the server |
Audio Codec | AAC-LC | Â |
Audio Sample Rate | 48 kHz | Â |
Channels | 2 (Stereo) | Any other number of channels (0, 1, 4...) is unsupported for h.264 on SX servers. |
Â
Server Video Resolution | Details |
NTSC | Â 720x486(480), 4:3 or 16:9 aspect ratio, 29.97 frames per second |
1080i | 1920x1080, 16:9 aspect ratio, 29.97 frames per second |
720p | 1280x720, 16:9 aspect ratio, 59.94 frames per second |
1080p | 1920x1080, 16:9 aspect ratio, 59.94 frames per second |
* HD file resolutions are only supported on HD servers.
Suggested Settings
The following settings may improve the quality of video that you generate.
Setting Name | Value | Notes |
Scan Mode | Interlaced for Interlaced output | e.g. If you are playing 1080i content on a 1080i channel, keeping the file interlaced will provide the best quality. |
Entropy Encoding | CABAC | Â |
Video Bitrate | For SD content: 1-2 mb/s | Depends on content, sports content will likely benefit from a higher bitrate. |
 |
For HD content: |
 |
GOP sizes |
15 frames |
Favor GOP sizes smaller than one second (N<30 in 29.97, N<60 in 59.94, optimal at ~15). |
Additional Information
A small collection of encoding profiles has been provided by our customers. Â See SX Encoding Profiles on labs.trms.com for more info.