also added to TODO here: https://wiki.blender.org/index.php/Dev:Source/Development/Todo/Scripting
Will have look again if time permits

I believe this is caused by an extreme value for bump (causing the normals to point in all kinds of directions). Or I'll quote @Brecht Van Lommel (brecht) from T54498:

Good joke! What means "don't know"? This problem is since 2013 or early. For 5 years you can't to know how resolve this problem? Why other render platforms can do this, and you can't? Or don't want to resolve?

Please don't reopen issues. At this moment we don't know when it will be solved.

Guys, April 2018, when u fix problem? Blender internal and Cycles have this problem{F2686577}. And don't say about subsurf, when i need lowpoly, with smooth normals. When?

Adding @Sergey Sharybin (sergey) & @Bastien Montagne (mont29) as after a quick search seem to be the most active on the subject of VSE Proxies.

First part has been fixed.
Second part fixed by @Sergey Sharybin (sergey) in D3083 rB370a2d6917eb

And .... now that I am home, I just tried playing the rendered mp4s on my pc and they play fine. So it is not a Blender issue but a Quicktime playback issue on the macs. I feel like an idiot for not having tried that before.

Today I tested a simple re-encoding of a 1000-frame section of an MOV file to a half-HD mp4 file using the Blender VSE on the Media/Art center Macs (which run Mac OS Sierra). I tested Blender versions 2.79, 2.79a and 2.79b ... all with the same result.

Hi - the media/art center is closed today for Easter Monday, so I will have to go there tomorrow to generate the bug output.

I will send you debug output and new zip file on Monday

I don't have permission to install anything on the machines at the media/art center, I just teach there sometimes. So I can't install 2.79b.

@Trudy Wohlleben (trudyvfx) Yeah that was for you. Run blender with debug options on:
open Terminal and start blender with:

doesn't seem like the attached .blend is using any of the video files, (or i'm not bright enough to figure out how to reset the paths) if you could attach a .blend file where we just have to hit 'render animation' to get the problem to show that be appreciated.

Is this question for me (probably not but answering just in case)?

I struggled with this problem for months. Used different computers, re-installed Blender, re-installed windows (I am using 8.1 & 10), installed new and old drivers for my Nvidia card, changed the TDR and everything I could think of...but no luck.

Was the file packed or just like that? Making sure that asset file paths are ok, that rendered out on 2.79b.
Debug output would be nice to trace the error, if it still is there.

output from clinfo:

Could you please find and run the program clinfo and attach the output, it will help in figuring out why your card is listed when it shouldn't be.

@Campbell Barton (campbellbarton) Polite nudge.
Just would like this looked over before 2.79b release...

I'm not using debug mode but I can choose my graphic card in system setting. But as You said it's first GCN generation.

It looks like your GPU is from GCN 1 generation. Its unfortunate, but support for those cards had to be dropped. Your card shouldn't have been available to select for GPU rendering, did you enable debug mode? This mode isn't meant for regular use, and cant be expected to function properly. If you didn't enable debug mode and were still able to select your card then that would be a bug we should fix.

Thanks, good to know! Can't wait for 2.8! :)

There is a feature like this in the latest builds:
https://wiki.blender.org/index.php/Dev:Ref/Release_Notes/2.80/Cycles#Optimizations

This is really a known to do item and not a bug, so closing, feature requests are handled elsewhere.

As a quick workaround, you can select a codec that has a Constant Rate Factor (CRF) labeled 'Output quality' (e.g. H.264) set it to 'None; use constant bit-rate' and switch back.

In D3097#73383, @Brecht Van Lommel (brecht) wrote:

I'm not sure what would be the purpose of showing it only the first time? If it would remember the frame range and frame rate values specified then, the user would have no way to change them the second time. If it wouldn't remember the values, why would they only be needed the first time?

Since last asking for information it has been 7 or more days, due to the policy of our bug tracker we will have to archive the report until the requested information is given.

Yes, I think iuser->layer should be automatically set to the active render layer when "Only render active layer" is enabled. This means changing render_image_restore_layer() behavior.

Definitely No to any kind of popup when hitting Ctrl+F11. Even if it's only once, it slows down and after that we still have the issue of where to set these settings.

In D3097#73382, @Christian Brinkmann (poor) wrote:

Ok, thanks @Brecht Van Lommel (brecht). I could imagine, getting that dialog the first time starting the playback per scene might feels good and does not slow down the user (also in case of OpenGL previews), only issue is how the get the dialog back if needed... I'd like to try that idea before adding a new menu entry. Please let me know, if you have any concerns about that.