Creating h.264 files that will work with my SX video server

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. In this guide, we will discuss the implications of and best settings for some of these variables. 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
Profile	Main or High
Video Codec	h.264
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
Audio Sample Rate	48 kHz
Channels	2 (Stereo)	Any other number of channels (0, 1, 4...) is unsupported for h.264 on SX servers.

Server Video Resolution	Details
NTSC	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
Video Bitrate	For SD content: 1-2 mb/s	Depends on content, sports content will likely benefit from a higher bitrate.
	For HD content: 2-5 mb/s
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. See SX Encoding Profiles on labs.trms.com for more info.