Bug reports regarding NVENC
Hi, where can I post bug reports about NVENC? As NVENC is part of the driver, is the driver feedback forum the right place? I've already posted this: https://forums.geforce.com/default/topic/1009796/nvenc-wrong-dar-if-image-size-is-720x576/ This was months ago, but the problem persists in the current release. This is a serious issue for me, and it disables me to use NVENC. It affects all applications that use NVENC, like FFMPEG or AviDemux. I know there are other encoders, but I'd like to make use of GPU accelerated encoding. I have so many Gigabytes of Videos in the pipeline waiting for being processed, but if the bug doesn't get fixed... Thanks
Hi,

where can I post bug reports about NVENC? As NVENC is part of the driver, is the driver feedback forum the right place? I've already posted this:
https://forums.geforce.com/default/topic/1009796/nvenc-wrong-dar-if-image-size-is-720x576/
This was months ago, but the problem persists in the current release. This is a serious issue for me, and it disables me to use NVENC. It affects all applications that use NVENC, like FFMPEG or AviDemux. I know there are other encoders, but I'd like to make use of GPU accelerated encoding. I have so many Gigabytes of Videos in the pipeline waiting for being processed, but if the bug doesn't get fixed...

Thanks

#1
Posted 08/14/2017 12:13 PM   
Hey, just referred ManuelG here from the latest release thread, hopefully he can put a bug in with the relevant team. Content of original thread [quote="CryGuyOriginal"]Hi, I was using ffmpeg and it's built-in "h264_nvenc" encoder. I stumbled across a bug that I reported to the ffmpeg bug tracker, but it turned out to be a general problem in the NVENC H.264 encoder, and it is not limited to ffmpeg. This means, it is also reproducable if I encode a video from C++ code utilizing nvenc. Problem description: When encoding a video with an image size of 720x576 while specifying DAR=16:9 (SAR=64:45), the encoder sets the aspect ratio of the encoded video incorrectly to DAR=20:11 (SAR=16:11). Link to ffmpeg bug ticket: https://trac.ffmpeg.org/ticket/6119 System: NVIDIA driver version 382.05, Geforce GTX 750 Ti, Windows 10 Pro x64 It would be really nice if this would be forwared to the Nvidia developer team as I do not want to register at developer.nvidia.com only for reporting this one problem. Thank you [/quote]
Hey, just referred ManuelG here from the latest release thread, hopefully he can put a bug in with the relevant team.

Content of original thread

CryGuyOriginal said:Hi,

I was using ffmpeg and it's built-in "h264_nvenc" encoder. I stumbled across a bug that I reported to the ffmpeg bug tracker, but it turned out to be a general problem in the NVENC H.264 encoder, and it is not limited to ffmpeg. This means, it is also reproducable if I encode a video from C++ code utilizing nvenc.

Problem description:
When encoding a video with an image size of 720x576 while specifying DAR=16:9 (SAR=64:45), the encoder sets the aspect ratio of the encoded video incorrectly to DAR=20:11 (SAR=16:11).

Link to ffmpeg bug ticket:
https://trac.ffmpeg.org/ticket/6119


System: NVIDIA driver version 382.05, Geforce GTX 750 Ti, Windows 10 Pro x64

It would be really nice if this would be forwared to the Nvidia developer team as I do not want to register at developer.nvidia.com only for reporting this one problem.

Thank you



In Memory of Chris "ChrisRay" Arthington, 1982-2010

Specs:
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Monitor:ROG PG279Q, BenQ BL2211, Sound:Creative XFI Titanium Fatal1ty Pro
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Case:NZXT Phantom 820, PSU:Seasonic X-850, OS:Windows 7 SP1
Cooler: ThermalRight Silver Arrow IB-E Extreme

WIP:
CPU:Intel Xeon x5660, Mainboard:Asus Rampage II Gene, Memory:16GB Corsair Vengeance 1600 LP
Video:EVGA Geforce GTX 680+ 4GB, Palit Geforce GTX 550ti
Monitor:Pending, Sound:Pending
SDD:Pending
HDD:Pending
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#2
Posted 08/14/2017 04:10 PM   
Sora, thank you.
Sora, thank you.

#3
Posted 08/15/2017 06:40 PM   
I don't know what to do. This will probably never be fixed. :(
I don't know what to do. This will probably never be fixed. :(

#4
Posted 10/01/2017 11:23 PM   
[quote="CryGuyOriginal"]I don't know what to do. This will probably never be fixed. :([/quote] had any changes with the r387 drivers?
CryGuyOriginal said:I don't know what to do. This will probably never be fixed. :(


had any changes with the r387 drivers?



In Memory of Chris "ChrisRay" Arthington, 1982-2010

Specs:
CPU:Intel Xeon x5690 @ 4.2Ghz, Mainboard:Asus Rampage III Extreme, Memory:48GB Corsair Vengeance LP 1600
Video:EVGA Geforce GTX 1080 Founders Edition, NVidia Geforce GTX 1060 Founders Edition
Monitor:ROG PG279Q, BenQ BL2211, Sound:Creative XFI Titanium Fatal1ty Pro
SDD:Crucial MX300 275, Crucial MX300 525, Crucial MX200 250
HDD:500GB Spinpoint F3, 1TB WD Black, 2TB WD Red, 1TB WD Black
Case:NZXT Phantom 820, PSU:Seasonic X-850, OS:Windows 7 SP1
Cooler: ThermalRight Silver Arrow IB-E Extreme

WIP:
CPU:Intel Xeon x5660, Mainboard:Asus Rampage II Gene, Memory:16GB Corsair Vengeance 1600 LP
Video:EVGA Geforce GTX 680+ 4GB, Palit Geforce GTX 550ti
Monitor:Pending, Sound:Pending
SDD:Pending
HDD:Pending
Case:NZXT Guardian 921RB, PSU:Corsair 620HX, OS:Windows 7 SP1
Cooler: ThermalRight True Spirit 120M

#5
Posted 10/16/2017 11:36 AM   
[quote="Sora"]had any changes with the r387 drivers?[/quote] I'm terribly sorry that I did not see your reply before! Haven't been here for a while, and I don't find where to enable mail notifications for topics here - if available at all. However, I've just subscribed to the RSS feed and won't miss anything anymore. Thanks for asking. No, the problem is still not fixed. If I force DAR=16:9, it still sets DAR 20:11. This is a deviation of 45:44 or ~2.3%, so the size of the displayed image is 1047x576 instead of correctly 1024x576.
Sora said:had any changes with the r387 drivers?

I'm terribly sorry that I did not see your reply before! Haven't been here for a while, and I don't find where to enable mail notifications for topics here - if available at all. However, I've just subscribed to the RSS feed and won't miss anything anymore.

Thanks for asking. No, the problem is still not fixed. If I force DAR=16:9, it still sets DAR 20:11. This is a deviation of 45:44 or ~2.3%, so the size of the displayed image is 1047x576 instead of correctly 1024x576.

#6
Posted 11/27/2017 11:35 PM   
Thanks for your feedback. I have filed a bug to see if we can reproduce the issue
Thanks for your feedback. I have filed a bug to see if we can reproduce the issue

We can't fix your bug if we can't reproduce it. Please provide as much details as possible including specs, steps to reproduce, graphics settings used, etc..

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#7
Posted 12/15/2017 10:01 PM   
I can confirm that this bug is reproducable. Used application: ffmpeg Input resolution: 720x576 [SAR 16:11 DAR 20:11] Desired output: 720x576 [SAR 64:45 DAR 16:9] Used command: ffmpeg -i INPUT -vf setdar=dar=16/9 -c:v h264_nvenc OUTPUT Unfortunately with [b]setdar=dar=16/9[/b] (or 1.777 or 1.778) the output resolution is 1047x576. With [b]setdar=dar=16/10[/b] (1.6) and [b]setdar=dar=16/8[/b] (2) the result are what they should be. So I assumed the problem is caused by the way it calculates the decimals. I did these tests: setdar=dar=1.789 => 1030x576 setdar=dar=1.78 => 1025x576 setdar=dar=1.779 => 1025x576 [i]setdar=dar=1.778 => [u]1047[/u]x576 setdar=dar=1.777 => [u]1047[/u]x576[/i] setdar=dar=1.776 => 1022x576 setdar=dar=1.775 => 1022x576 setdar=dar=1.77 => 1019x576 setdar=dar=1.765 => 1016x576 setdar=dar=1.76 => 1013x576 Quite interesting, isn't it?
I can confirm that this bug is reproducable.

Used application: ffmpeg
Input resolution: 720x576 [SAR 16:11 DAR 20:11]
Desired output: 720x576 [SAR 64:45 DAR 16:9]
Used command: ffmpeg -i INPUT -vf setdar=dar=16/9 -c:v h264_nvenc OUTPUT

Unfortunately with setdar=dar=16/9 (or 1.777 or 1.778) the output resolution is 1047x576.

With setdar=dar=16/10 (1.6) and setdar=dar=16/8 (2) the result are what they should be.

So I assumed the problem is caused by the way it calculates the decimals. I did these tests:

setdar=dar=1.789 => 1030x576
setdar=dar=1.78 => 1025x576
setdar=dar=1.779 => 1025x576
setdar=dar=1.778 => 1047x576
setdar=dar=1.777 => 1047x576

setdar=dar=1.776 => 1022x576
setdar=dar=1.775 => 1022x576
setdar=dar=1.77 => 1019x576
setdar=dar=1.765 => 1016x576
setdar=dar=1.76 => 1013x576

Quite interesting, isn't it?

#8
Posted 01/27/2018 11:54 PM   
Thanks for confirming. FFmpeg is creating a fraction from the decimals before passing it to the encoder. FFmpeg computes it correctly, but the encoder has a problem with only just this resolution and aspect ratio. For example, if you resize to 900x720 - which is the same factor of 1.25 like it is with 720x576 - and specify DAR=16:9, the output is correct and correctly displayed at 1280x720: ffmpeg -i d:\in.ts -vf scale=900x720 -aspect 16:9 -c:v h264_nvenc d:\out.mp4 => 16:9 (correct) ffmpeg -i d:\in.ts -vf scale=720x576 -aspect 16:9 -c:v h264_nvenc d:\out.mp4 => 20:11 (wrong) As I wrote a test application that doesn't use FFmpeg, directly feeds the encoder and suffers from the same problem, I'm sure that it's not an FFmpeg issue. (Probably the "resolution" is the counter question "Who is watching TV in SD nowadays???" I do, because a) I always did and I never had and don't have a problem with it, b) I don't have a DVB-S2 card (my current one is DVB-S and still working well), c) several free TV channels are only available via "HD+" which is not a convincing system yet)
Thanks for confirming.

FFmpeg is creating a fraction from the decimals before passing it to the encoder. FFmpeg computes it correctly, but the encoder has a problem with only just this resolution and aspect ratio. For example, if you resize to 900x720 - which is the same factor of 1.25 like it is with 720x576 - and specify DAR=16:9, the output is correct and correctly displayed at 1280x720:

ffmpeg -i d:\in.ts -vf scale=900x720 -aspect 16:9 -c:v h264_nvenc d:\out.mp4
=> 16:9 (correct)

ffmpeg -i d:\in.ts -vf scale=720x576 -aspect 16:9 -c:v h264_nvenc d:\out.mp4
=> 20:11 (wrong)

As I wrote a test application that doesn't use FFmpeg, directly feeds the encoder and suffers from the same problem, I'm sure that it's not an FFmpeg issue.


(Probably the "resolution" is the counter question "Who is watching TV in SD nowadays???" I do, because a) I always did and I never had and don't have a problem with it, b) I don't have a DVB-S2 card (my current one is DVB-S and still working well), c) several free TV channels are only available via "HD+" which is not a convincing system yet)

#9
Posted 01/28/2018 12:58 AM   
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