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1. Re: Low bitrate target not honored
ExactImage Aug 23, 2011 10:32 AM (in response to Howard Hoffman)Target bit rate is just that - a target. If you are moving on photos then it may not be able to hit your target based on how much it changing in the frames - hence the allowance for a higher rate.
Set your highest rate to a lower number and render just a short section and see how the quality looks then....
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2. Re: Low bitrate target not honored
Howard Hoffman Aug 23, 2011 10:42 AM (in response to ExactImage)I can understand it deviate a bit, but not from 7 to 35. This does not make sense.
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3. Re: Low bitrate target not honored
digitlman Aug 23, 2011 10:46 AM (in response to Howard Hoffman)You are correct, it should average 7mbit only of that is your target. Something is wrong, are you sure the length is correct? maybe your work area is set to have extra dead space at the end?
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4. Re: Low bitrate target not honored
Howard Hoffman Aug 23, 2011 10:51 AM (in response to digitlman)The video length looks correct.
I did find CS5 AME tends to have the wrong encoding area by default so I have been manually correct all the time.
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5. Re: Low bitrate target not honored
Jeff Bellune Aug 23, 2011 10:53 AM (in response to Howard Hoffman)Check your CBR bitrate. I bet it's close to 35 Mbps. Set the CBR bitrate to 7, then go back and set the 2-pass VBR bitrate to 7. This time, the 7 Mbps setting should stick and you should get an appropriately-sized output file.
-Jeff
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6. Re: Low bitrate target not honored
JSS1138 Aug 23, 2011 10:54 AM (in response to Howard Hoffman)not from 7 to 35. This does not make sense.
It does if you have 7 set as the target and 35 set as the max.
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7. Re: Low bitrate target not honored
Howard Hoffman Aug 23, 2011 10:59 AM (in response to JSS1138)CBR at 25. If I choose CBR and set it at 7, close the dialog, it goes back to 25.
Jim, what do you mean? Do you mean the target is useless?
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8. Re: Low bitrate target not honored
JSS1138 Aug 23, 2011 1:28 PM (in response to Howard Hoffman)No, I mean if you set the VBR target to 7, and the VBR max to 35, it is no surprise that the bitrate might well peak at 35.
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9. Re: Low bitrate target not honored
Howard Hoffman Aug 23, 2011 1:34 PM (in response to JSS1138)I take the result file size (video), get the total number of bits, divided by the total length in seconds, I get 34.xxx Mbps. I don't think this is right.
In CBR, it always reset to 25 if I set it lower.
In VBR 1 or 2 pass, the estimate size looks correct and the target remains at what I set. But the result file is 34.xxx Mbps. I recently installed quicktime. Could that be the problem?
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10. Re: Low bitrate target not honored
Howard Hoffman Aug 23, 2011 5:41 PM (in response to Howard Hoffman)I did an experiment with 3 encoding all with VBR 1-pass target 10 Mbps, 35 max
1. Video only
2. Video and Audio, no mux
3. TS Mux
1 and 2 resulted in m2v of 3.6 Mbps
3. resulted in m2ts of about 35 Mbps
I then tried VBR 2-pass, same result.
I now think there is some variation in low bit rate. However, the muxing is the real problem. There is choice of bitrate type being constant. I wonder if AME does not support muxing of VBR.
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11. Re: Low bitrate target not honored
digitlman Aug 24, 2011 5:31 AM (in response to Howard Hoffman)function(){return A.apply(null,[this].concat($A(arguments)))}
Howard Hoffman wrote:
I did an experiment with 3 encoding all with VBR 1-pass target 10 Mbps, 35 max
1. Video only
2. Video and Audio, no mux
3. TS Mux
1 and 2 resulted in m2v of 3.6 Mbps
3. resulted in m2ts of about 35 Mbps
I then tried VBR 2-pass, same result.
I now think there is some variation in low bit rate. However, the muxing is the real problem. There is choice of bitrate type being constant. I wonder if AME does not support muxing of VBR.
One last verification: what are you looking at the bitrate with? is it reporting it incorrectly?
What are the actual resulting file sizes of those three tests?
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12. Re: Low bitrate target not honored
JSS1138 Aug 24, 2011 1:12 PM (in response to Howard Hoffman)3. resulted in m2ts of about 35 Mbps
Looks like the audio is taking up a whole lot of space.
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13. Re: Low bitrate target not honored
Howard Hoffman Aug 24, 2011 4:26 PM (in response to digitlman)I am calculating bitrate by filesize divided by media length. MediaInfo reports the same results but I am doing math myself.
No, it's not the audio. I can demux the m2t file and the audio is AC3 at 192 kbps. It's the video that's 35 Mbps.
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14. Re: Low bitrate target not honored
JSS1138 Aug 25, 2011 12:13 PM (in response to Howard Hoffman)I wouldn't trust your math or MediaInfo. The first doesn't account for audio or other file overhead, and the latter has been wrong on occasion.
Given that unmuxed, the video only file is small, and the muxed video and audio file is large, that is a veeeery strong indicator that the largess is due primarily to the audio. You sure about those settings?
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15. Re: Low bitrate target not honored
Howard Hoffman Aug 25, 2011 6:04 PM (in response to JSS1138)To make it clear, I demuxed the mt2 to m4v and ac3 (in seconds so no way re-encoding happened). m4v is 35 Mbps and ac3 is 192 kbps. The math of simple division can hardly go wrong.
To me, it seems to be a simple bug or feature limitation. The thing I don't like about is it's silent.
Can anyone do a short test? 60 seconds clip barely takes much time.
Thanks!
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16. Re: Low bitrate target not honored
Howard Hoffman Sep 17, 2011 5:47 PM (in response to Howard Hoffman)Just returned from vacation. Has anyone tried it?
In the multiplexing tab, it has an option for MPEG (constant vs variable) but no option (only constant) for H.264.
Can someone confirm this is a feature limitation?
Thanks!
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17. Re: Low bitrate target not honored
Stan Jones Sep 17, 2011 8:11 PM (in response to Howard Hoffman)Short sample. H.264-bluray. Demuxed only; I realize you are concerned about muxing, but the initial problem you present here was demuxed. I looked at datarate of only video (m4v). CS5 (not 5.5). Used AME queue.
3 conditions:
CBR 7;
VBR 1 pass, target 7, max 35;
VBR 2 pass, target 7, max 35.
Resulting m4v was 7.11, 6.82, and 7.11 Mbps respectively.
In other words, I saw no problem with datarates matching what I set.
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18. Re: Low bitrate target not honored
Howard Hoffman Sep 17, 2011 8:16 PM (in response to Stan Jones)I can't edit the title any more. Yes, the problem is only when muxing is on. If it's demuxed, there is no problem.
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19. Re: Low bitrate target not honored
Stan Jones Sep 17, 2011 10:09 PM (in response to Howard Hoffman)I can't test it with 5.5, but I get the problem you describe in 5.0.3.
You can see this without doing the exports. Look at the "Estimated File Size" with the audio and video rates set. Then just click on the mux option, and watch them increase dramatically.
I brought the CBR7 muxed and not muxed as timelines into Encore. They both show as "Do Not Transcode" for the BD settings. I built a BD folder. The sizes and datarates carried through - meaning that Encore muxes them without adding the size/datarate that Premiere/AME does.
So I have to conclude it is a bug. What else could it be?
Can anyone confirm this in 5.5?
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20. Re: Low bitrate target not honored
Howard Hoffman Nov 13, 2012 8:14 PM (in response to Stan Jones)Bug remains in CS 6. Can Adobe look at it?
Thanks




