I have the latest version of Adobe media encoder installed and have had the same problem for over a year now. I do a lot of computer screen recordings that do not have a video camera feed and or just presentation based. No matter what CBR settings I I try in Adobe media encoder, the final export always seems to be variable and significantly lower than the chosen data rate. If I use CBR for a video camera recording, the output is still variable according to media info but the data rate is a lot closer to what I choose in Adobe media encoder. I feel like I Adobe media encoder is still doing some variable bit rate analysis to screen based only recordings for some reason. Any thoughts or suggestions would be greatly appreciated.
Does your screen recording source video use variable frame rates? Premiere only supports constant frame-rate video so perhaps that's why the encoder is not acting as expected for CBR renders.
I actually use Atomos Blade recorders with ProRes LT as the source recorder for these 720p60 screen recordings. I wouldn't think that would cause any problems with Adobe Media Encoder and CBR but I suppose ProRes technically isn't a CBR source format? I will definitely have to test further. Thanks so much for your response. I really appreciate it. I did notice the following link that seems to be a similar issue but the thread seems closed although I am still having a similar problem with MediaInfo saying a CBR encoding from AME is variable. All continued thoughts are welcomed. Warmest Regards! NM
Anyone have any other thoughts? I am bumping my thread again bc I still don't have a resolution of how to consistently export CBR only Mp4 / h.264 files with the latest version of AME. Any help would be GREATLY appreciated.
I'm still unsure whether the media you're working is CFR or VFR ... those are frame-rate, constant versus variable. Constant & variable bit rate is of course a very different thing. Although some folks especially at first are unsure about CFR/CBR/VFR/VBR ... it's confusing.
So ... how about downloading MediaInfo, dropping a file on it, and going into that app's Tree view ... take a screen grab of the video section, and post it back here using the flower icon in the middle of the reply box formatting bar.
Media Info: https://mediaarea.net/en/MediaInfo
Thanks so much for responding so quickly. I will post a screenshot shortly and am very well aware of MediaInfo. That is what I have been using to help troubleshoot this issue. For what it is worth, my source files are 720p60 ProRes....which by nature I suppose can be Variable.
But, the big question is, shouldn't AME be able to export CBR files with a constant frame-rate REGARDLESS of what the original source bitrate (Variable vs Constant) or frame-rate (constant versus variable) is?
Perhaps I am just giving AME touch much credit for what I assume it can do 😉
Depending on the preset & settings, AME can produce CBR files. It's not particularly good at the VFR/CFR conversion from my testing, however. And if it's working with a VFR file to begin with, it can seem to be a bit confused. Which could be the issue you're having, but will be easier to determine when you post the file data.
Harley T Davis is a user that has posted a ton on here on the ways to try and get the best CFR out of a transcode involving VFR material ... and I've tried his suggestions. I get better results from my own presets I've made in HandBrake, and so any VFR material I've got (and I'm using more Samsung S7 phone clips these days, weird to say) goes immediately into an over-night or lunch-time queue in HandBrake.
Then ... I can use AME for transcodes to Cineform or DNxHD/R if I choose to do so and get expected results.
In Handbrake ... you need to both click the little circle by "CFR" and set a specific number frame-rate, as if you use an 'auto' or 'same-as source' setting there you get VFR out if you had VFR in. Also, it assumes you want a ton of compression in all it's presets, so I had to set the compression settings close to "placebo" to get the full size of my files out.
Here is a screenshot of my current source file. Please note, the content of this file is a computer based PowerPoint presentation that was recorded using an Atomos Ninja Blade via HDMI at 720p60. Please review my original post at the top of this thread as well bc AME definitely seems to behave differently with screen/computer/presentation based recording files vs camera based recording files. Again, any help would be GREATLY appreciated.
At the end of the day, all I would like to do is export a CBR h264 video file from AME regardless of what the source file is at the exact data rate and frame rate I choose in the AME settings. If I choose 1280x720 30p with a 3Mbps CBR data rate, I would expect to get those exact export settings and nothing different. And so far, my many hours of testing have unfortunately proven otherwise.
Does my issue make sense?
Ok, so if that's the "input" file, out of the Atomos, it's CFR ... good to know.
And that file is as shown, VBR, variable bit rate. But with a probably 'average' of around 85 Mbps, you've got plenty to work from.
So ... 3Mbps is a pretty low setting, from that choice I take it that file size is more important than image quality ... what is the rate you're actually getting from AME after export?
I just took a 6 minute recorded presentation portion from that large source file and used the following default H.264 AME Preset of HD 720p 29.97 for kicks with only changing the default VBR of that preset to CBR. Please see the following screenshots
Unfortunately, the resulting exported h264 file is NOT CBR and does NOT have a 6Mbps video data rate as shown by the 2180Kbps below....hence my problem. Now, the reason for this whole inquiry is that a streaming platform vendor I am working with requires all of my files to be delivered with certain exact CBR specifications and right now my data rate is all over the place and not consistent with what my AME export settings show. Using Handbrake is unfortunately not an option either bc my entire workflow depends on dynamic linking hundreds of files from Premiere to AME for direct rendering.
Thanks for confirming Neil! I really hope we can get to the bottom of this. For some reason, I just think that AME is still doing VBR based on what the content is despite the CBR still being selected. If you run video camera source recordings through AME as CBR you actually get closer expected Data Rates but if you run computer based screen recordings through AME as CBR the data rates vary greatly. I have even tried switching up keyframe values and also tried this on multiple computers. In short, I haven't been able to get AME to reliably produce actual constant bitrate exports. I realize the industry is going to VBR but some of us still need a reliable CBR export option.
I can't find it in the latest Premiere but there used to be an 'Optimise for stills' check box that reduced the data rate for static images, perhaps a screen recording is regarded as static.
Hmmm, good point. I don't recall seeing that option. Could be a possibility, though, if that was still available. Hopefully we can get some support on this thread from the powers that be. Thanks so much for taking the time to respond.
Anyone directly from Adobe have any thoughts on this thread? The problem is still there. Just bumping the thread to see if anyone has other thoughts?
Thanks for being so quick to help bump this thread again Neil! I really appreciate it. Fingers are still crossed.
I just submitted a bug form per your suggestion. I am hoping this is an easy resolution because I really need AME to export reliable CBR footage by the first of November 2017....fingers are crossed for a solution soon.
Kevin-Monahan ... Stefan Gruenwedel ... Any updates on this confirmed AME CBR export problem after I sent a big report in about a month ago? I really need this issue resolved by November for a major job of at all possible. Otherwise I might have to resort to a very long workflow involving Handbrake that I would rather not have to do.
I'm having this issue as well. Need to export as CBR per local broadcast station specs...of course the data reads as variable...
Yes, I am really really hoping that Adobe can fix this ASAP. This is a long standing proven BUG that needs to be resolved permanently. CBR should be CBR regardless of whether the video content is static or heavy motion, etc. And, likewise, VBR should be VBR. Not sure what AME is really doing under the hood but I hope it is straight forward to fix SOON. I have already submitted a case but feel free to submit another one elizabethc71898284!
I just filled out a "bug" form (probably useless) and chatted with online support. No luck so far...so frustrating.
The bug/feature forms are actually distributed in collated form to all management types, I've been told ... they do see how many of any particular thing are out there.
Now ... as to what gets worked on, it tends to boil down to how large a percentage of the user base is affected by an issue. Something that affects more people will tend to get worked on first for budgetary/time constraints. Which is naturally very frustrating if your issue is one that they only note a small number (relatively speaking) of problems with, among the total base.
Been there done that ... but ... the more of the bug reports filed, the higher any one issue gets on the list.