Roku Developer Program

[b14d3]

I'm looking at a series of different bitrates, so naturally a percentage-type system seems to work best in my head, but I'm confused about which to use. For example, the one that I've got in my head is like this:

100% (native bitrate for the video)
80%
65%
50%

This seems to be ok on paper, without degrading the quality to the point that it is unwatchable. But I need your help on any suggestions, or what you've found to work for you.

All help is greatly appreciated 🙂

[Anonymous]

The encodings guide provides some suggestions and guidelines:

http://sdkdocs.roku.com/display/RokuSDK ... ding+Guide

[b14d3]

Reading through it, it appears to use 100%, 75%, and then 37.5% which seems like an extreme jump for most video, especially since the content I have doesn't have a particularly high bitrate to begin with. Does anyone have any in-practice scale to see what other people have done that has worked?

[destruk]

I'm not sure what you are referring to in reference to percentages? I think for variable bitrate, if you are using that, you will need to determine your own best setting to use based on your content. ie fast action scenes with backgrounds that blur you'll want to use a higher peak limit to keep clarity, where still frames for intro titles you'll want to lower the bitrate requirement. If you want anyone to give you hard and fast numbers or encoding profiles I don't think you'll be pleased with the efficiency of the result and it's quicker to simply use CBR.

Hard recommendations for CBR are specified in the same page
Sports:
#1. 800 kbps
#2. 1386 kbps
#3 1800 kbps
#4. 2400 kbps (HD)
#5. 3200 kbps (HD)
Movie Library:
#1. 664 kbps
#2. 996 kbps
#3. 1320 kbps
#4. 2600 kbps (HD)
#5 3800 kbps (HD 1080p)
College Lectures:
#1. 394 kbps
#2. 664 kbps
#3. 996 kbps
#4.1500 kbps
#5.2000 kbps (HD)


As for the CBR percentages (relative percentage of highest quality) - I always thought it was based on the client's available bandwidth from their ISP. So if you have low end DSL your maximum bitrate for smooth playback actually could be as low as 200 kbps. - taken from AT&T
AT&T High Speed Internet Basic
FastAccess DSL Lite 200 Kbps - 768 Kbps

If your lowest possible bitrate for your content is too high then nobody with AT&T DSL could ever watch it. Most people have at least 300KBPS broadband.
AT&T High Speed Internet Express
FastAccess DSL Ultra 769 Kbps - 1.5 Mbps

standard service is between these - which covers bitrates 2-4

If you have faster service than this, then you're good to go, and since roku autoselects based on your own measured bandwidth, this is the reason the 'recommended cbr speeds' are as they are, not because of a percentage of quality, but moreso for the actual viability of your content selection among possible viewers.