Preliminary Survey Results – CBR, VBR and Capped CRF – $100 Amazon Gift Card Incentive

On January 13th, 2016, I launched a survey to determine the bitrate control techniques most commonly used by streaming producers. Some preliminary results are in, but the number of respondents is too small to draw any conclusions. I wanted to publish the data to stimulate additional interest, and also announce that I am sweetening the pot with a $100 Amazon gift card to be awarded to a random respondent (including those who have already responded).

I will share the results in a webinar entitled, Content-Aware Encoding-Applying Lessons Learned from Netflix’s Per-Title Optimization Blog Post, scheduled for January 26th at 2:00 PM EST. If you complete the survey, I will send you a coupon code worth a $10 reduction in the cost of the webinar (from $29 to $19). For those who don’t plan to attend the webinar, I’ll publish the results on this website as well.

Here are the results from the first seven respondents.


Though there are only seven respondents, four are producing over 100 files per week, so they represent fairly significant video producers.


Not surprisingly, HLS was the dominant ABR format produced by the group. Note that respondents can choose multiple formats when answering this question. 


The producers used a pretty good mix of bit rate control techniques, including capped CRF, an interesting technique I will cover in detail in the webinar. Again, respondents could choose multiple answers to this question. 


Here’s where things get interesting. Of those using constrained VBR, two respondents used 110% of the target, which may be just enough VBR to avoid the occasional artifacts that CBR can produce. The 110% target is also (presumably) designed to keep the encoded files within the 110% variability threshold dictated by Apple’s Tech Note TN 2224.


This is the slide I found most interesting. Of the producers outputting HLS streams, half follow the 110% dictate religiously, while the other half ignore it completely.

Again, while these results are very interesting, the numbers are statistically insignificant. I would greatly appreciate your taking the time to share your own practices, which will help all producers understand the current state of the state. And hey, you could be one lucky winner of a $100 Amazon Gift card.

About Jan Ozer

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I help companies train new technical hires in streaming media-related positions; I also help companies optimize their codec selections and encoding stacks and evaluate new encoders and codecs. I am a contributing editor to Streaming Media Magazine, writing about codecs and encoding tools. I have written multiple authoritative books on video encoding, including Video Encoding by the Numbers: Eliminate the Guesswork from your Streaming Video ( and Learn to Produce Video with FFmpeg: In Thirty Minutes or Less ( I have multiple courses relating to streaming media production, all available at I currently work as as a Senior Director in Marketing.

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