Saving the .blend and do a succesful render and then adding a space character to the filepath, without saving the .blend gives this error in the latter part of the render session:

(It seems like the same moment in the render process the error comes as exporting in AVI RAW?)

I am not sure how hard this will be though.

How to stop Parallel Render ?
I just pressed ESC and the Blender info log / render message changed, but did not stop rendering...

When generating a specific batch item to a separate video Blender can crash (for various reasons, unrelated to this addon).
This will leave output directory with a file that seemingly has been done, however it will be corrupt.

To ease with possible confusion on what was generated fully and what crashed render should happen to a temporary/different name to final result and only rename to expected output once render has successfully finished.

The Concatenating feature for ParallelRender doesn't create a combined file for me.

Maybe try looking at a script like VSRender to see what it does. Whenever I concatenate with that, it works. Maybe it has to do with it being a separate feature there and not automatically done like in ParallelRender?

Are you going to update your great Parallel Render script? :-)

If you want to add an 'open file' button and dialog in the Parallel Render Settings for locating FFmpeg, I found a working snippet, which shows how to do that: https://blender.stackexchange.com/questions/26898/how-to-create-a-folder-dialog/26906#26906

Can't find any examples using this function:
https://docs.blender.org/api/blender_python_api_2_76_9/bpy.ops.buttons.html

Makes it easier to use when you reload project file you don't have to set up everything.

I realized that exports with AVI JPEG is way faster than using the ffmpeg option, and it is even faster with PR, however AVI JPEG doesn't export with audio.

910 HD frames(PR cuts 48 sec.):
AVI JPG | 100.00% | No PR  |   | 1.57
AVI JPG | 100.00% | PR 4/4 |   | 1.09|  

Maybe, for as fast as possible renders, and if AVI JPEG is selected as export option, a mixdown could be run afterwards and then muxed with the avi using ffmpeg?
Mixdown in API

I installed the Parallel Render addon, but the preferences aren't showing for me.

Also, the render setup isn't showing for me either (the window after pressing space and typing parallel render). It just leads to this:

Am I missing something??

Currently to use add-on you have to know to find the operator name and kick it off from there.
It could be nicer if there was a button along "Render Animation".

Hi. I unpacked the .zip, unpacked the "addon" folder, and re .zip it. Targeted it back in Blender>addons, but it doesn't show the VSE addon to activate it.
I also downloaded the ktba master.zip, installed through addons, but the VSE addon is not listed (I guess it is because it is 2.79 version?)

How do I install this correctly?
Thanks.

One of the Blender devs, LazyDodo, wrote to me: "if you render from the UI it'll generally do the color management in glsl which will appear single-threaded, when doing a CLI render, OpenGL is not used, and it'll run multithreaded on the cpu"

First I tried to render a 100 frames of a color strip, using Parallel Render, with just one instance and one part and it seemed to render as fast as the native Blender render(which actually used all 4 cores on my computer), spitting it into 4 instances and 8 parts seemed to render at least 10 sec. longer.

But maybe the speed enhancements are when rendering multiple tracks doing compositing?

Would ParallelRender work with Blender version 3.0?

I'm getting this error on Win 8:
https://preview.ibb.co/dGYYee/ffmpeg_error.png

I noticed that Parallel Render will only work with the mpeg-4 container and a h.264 codec when using Ffmpeg video. I guess, that this is not a bug, but probably a limitation. Apparently, ffmpeg does not have a codec limitation when concatenating media files. Is this an extension issue? Anyway, not having the right container and codec will cause errors, so maybe a check is needed, if these settings are correct, and inform the user if they are not correct.

I can see a progress bar that ends in 100% http://pasteall.org/pic/index.php?id=118260
Running from Terminal ends with http://pasteall.org/pic/index.php?id=118261
... but there is not any output (video) file on my iMac (OS X 10.11.6) with official 2.78c or today downloaded buildboot of 2.79.

Also does exist any detailed description of addon? I understood number of "instances" should goes to number of cores (for 2 core processor should it be set 2, right?), but what I don't understand is the rest system, probably because I don't see the result - "Number of batches". What batch means in this case. Thanks for more details.

Rendering with an audio codec selected and mixdown unchecked, will result in dropouts in the audio track.

Rendering with an audio codec selected(ex. mp4, h.264, ac3) and mixdown checked, will result in dropouts in the audio track.

Rendering AVI JPEG and mixdown checked, will result in dropouts in the audio track.

So, maybe it is necessary to do something like this to overwrite the audio when mixdown is checked? Or even strip the audio from the rendered file and then mux the mixdown audio in?
https://superuser.com/questions/602662/how-do-i-replace-the-audio-in-an-mp4-file-without-re-encoding

If no audio codec is selected, there are no dropouts in the audio.

If the .blend project isn't saved before running Parallel Render, it will cause an error and stop the export.

On the same note, if ex. resolution is changed after the .blend is saved it will not have an effect on the Parallel Rendered file. So, in other words, you'll have to save the .blend each time anything has been changed, to have effect on the render.

Here's a bit on how to check it: https://blender.stackexchange.com/questions/58711/python-check-if-file-was-saved

Sorry for opening as issue (for some reason "Pull request" doesn't want me to open new one.
(Or I missed something.)

• One thing that would really help - if script can remember last config.
  (rendering is repetitive task ... you know, again and again is something wrong in animation :) )

• Merge parts together
  There is another script, you probably know, that is not so under fingers as yours, but he use ffmpeg for merge. https://github.com/mikeycal/the-video-editors-render-script-for-blender

• Ability to set Relative path for output directory

Thanks for your opinion

I'm getting errors running this addon. It seems to produce 6 mp4 files as expected, but only one of them actually works. The other 5 appear corrupted, and cant be played in VLC. Also, the concatenate doesn't seem to be happening, maybe due to the errors?

I looked at Blender's logs and here's what I found:

Error   : EXCEPTION_ACCESS_VIOLATION
Address : 0x00007FF6D3298B7B
Module  : blender.exe
Thread  : 000032ac
Writing: C:\Users\USER\AppData\Local\Temp\Video_Edits_3.crash.txt
Append frame 5768
 Time: 00:00.16 (Saving: 00:00.03)

Its getting an access violation. I wonder why? I'm not running out of space or anything, and I don't think any of my files are locked or anything. I can send the crash.txt file if need be.

As it says on the tin.
Currently relative path as output dir puts files not where one would expect it.

Maybe I have forgotten something form the last time I tried your add on, but in 2.83 alpha ffmpeg doesn't seem to be detected, and concatenate doesn't seem to be enabled, though I can run the exports:

My path to ffmpeg is: C:\Users\user\Downloads\ffmpeg-20190926-87ddf9f-win64-static\bin\ffmpeg.exe
(On windows)

BTW. I noticed another way to export from blender, but I haven't tested it yet: https://github.com/tin2tin/Blender_with_ffmpeg

First i want to say, this is a great addon, I have been wanting to code something like this for a while, but it looks like I dont need to now :)

I would say tho that this script should probably render to image sequences only, if not required, it should at least be suggested, and definitely should be an option. For any larger projects (I just finished editing a 2 hour movie...) doing an image sequence pre-render, then pushing that to a final export is pretty much essential.

Some reasons for it:

1. Depending on the movie format, lots of short segments could have issues with frames not matching up properly, and there's always the problem of quality loss from 'a copy of a copy'.
2. Image sequences could be easily re-rendered directly in blender (not needing ffmpeg external), and the script could create a scene specifically for that render when it finishes.
3. I'm not sure how (or if) your script handles partial renders (wont the videos be partially written and thus corrupted?), with image sequences the script can check the render directory for what it still needs to rendered and only do those frames.

The parts are rendered fine, but when it comes to concatenating, it fails. Is this only happening here?