test the maximum bitrate of an encoded file

[Craig Seeman]

Bitrate Viewer is really good because you can see the bitrate frame by frame so you’ll not only know the max but know exactly where as well.
https://www.winhoros.de/docs/bitrate-viewer/

[Bob Cole]

Thanks very much! This is a great tool. I’m using it for an .flv – hope that works.

Having seen that the peaks of my 300kbps video go all the way up to 620kbps, I’m concerned, and wonder what to do about it.

Is there any way to tell Adobe Media Encoder to clamp down on the bitrate? If I lower the target bitrate to some absurdly low figure, I might be able to get the seven or so peaks under the mandated 400kbps. But I’d rather keep the average bitrate up higher.

Advice would be most welcome!

Bob C

[Craig Seeman]

I don’t have Adobe Media Encoder but some encoder have a Peak Bit Rate Constrained mode or equivalent means to designate a peak bit rate in addition to an average bit rate. This is usually found as part of Two Pass VBR encoding.

[Bob Cole]

It doesn’t “never fail,” but often enough… Having asked the question, I’ve stumbled across what I think may be the answer. Enabling two-pass encoding opens up a new set of sliders, including a maximum bitrate percentage over the average bitrate allowed.

If this works… I’ll post it just in case someone else is interested. If someone else knows this won’t work, I’d be curious about that.

Bob C

[Bob Cole]

Here is something odd: Bitrate Viewer shows the file to have peaks almost to 700kbps, but the client’s software shows the file to be peaking under 400kbps, and therefore perfectly acceptable. Mystifying, hunh?

Bob C

[Craig Seeman]

What software is your client using?
Perhaps their software measures over a set duration which may be averaging the peaks.

[Bob Cole]

You are correct.

I still have the original concern about how to make Adobe Media Encoder obey its own rules. AME creates files that, according to Bitrate Viewer anyway, have peaks double the “maximum” permitted.

Bob C

[Craig Seeman]

It’s not uncommon, unfortunately, for encoders to go past their peak settings. I believe it’s hard to “enforce” with certain codecs.

[Bob Cole]

I used BitRate Viewer to identify precisely where the peaks occurred. I assumed it was my “fault” — because I had done some panning and zooming on graphics.

One of the peaks was on such a pan and zoom. But by far the majority were on simple cuts from a wide shot to a medium close-up. Not much I can do about that.

I was using Adobe Media Encoder to create .flv files. Nothing out of the encoder’s comfort zone, for sure.

I’m not even sure whether this is “a problem that is a problem,” or whether occasional peaks are okay. But I’d like to know. We spend so much effort trying to write good scripts, create great pictures, edit with pace, etc. — but we (okay, I) neglect the compression area. And the viewer experience, online, can be severely compromised by jittery playback and occasional freezes.

Bob C

[Craig Seeman]

Does AME allow you to set a peak bit rate?
Is it exceeding it?
By how much?

Generally I find peaks aren’t much of a problem but if someone has lower bandwidth than the peak, it’s possible to get a pause while the frames buffer.