Background rendering with frame jump and sequencer is broken #52583

New Issue

Massimiliano Leoni · 2017-08-29T15:43:20+02:00

2017-08-29 15:43:20 +02:00

System Information
Linux Ubuntu 16.04, Intel integrated graphics card

Blender Version
Broken: at least from 2.76b to latest build

Short description of error
While rendering in the background from the command line a scene with a non-empty video sequencer, the jump parameter is ignored and the incorrect frames are rendered.

Exact steps for others to reproduce the error
Consider the attached bug.blend file bug.blend and run in the terminal the command

    blender -b bug.blend -a

Now all the 30 frames are correctly created.

If, instead, the couple of commands

    blender -b bug.blend -s 1 -j 2 -a
    blender -b bug.blend -s 2 -j 2 -a

is run, the wrong frames are generated. In particular, the second command generates the even-numbered frames but with the contents of the odd-numbered frames. Moreover, the terminal output highlights the inconsistency:

Fra:29 Mem:16.95M (0.00M, Peak 17.47M) | Time:00:00.58 | Remaining:00:00.00 | Mem:0.49M, Peak:0.87M | Scene, RenderLayer | Path Tracing Tile 132/135
Fra:29 Mem:16.89M (0.00M, Peak 17.47M) | Time:00:00.58 | Remaining:00:00.00 | Mem:0.43M, Peak:0.87M | Scene, RenderLayer | Path Tracing Tile 133/135
Fra:29 Mem:16.83M (0.00M, Peak 17.47M) | Time:00:00.58 | Remaining:00:00.00 | Mem:0.36M, Peak:0.87M | Scene, RenderLayer | Path Tracing Tile 134/135, Sample 3/10
Fra:29 Mem:16.77M (0.00M, Peak 17.47M) | Time:00:00.58 | Mem:0.30M, Peak:0.87M | Scene, RenderLayer | Path Tracing Tile 135/135
Fra:29 Mem:16.77M (0.00M, Peak 17.47M) | Time:00:00.58 | Mem:0.30M, Peak:0.87M | Scene, RenderLayer | Finished
Fra:29 Mem:16.43M (0.00M, Peak 17.47M) | Time:00:00.58 | Sce: Scene Ve:0 Fa:0 La:0
Fra:29 Mem:34.25M (0.00M, Peak 44.14M) | Time:00:00.62 | Sce: Scene Ve:0 Fa:0 La:0
Fra:29 Mem:34.25M (0.00M, Peak 44.14M) | Time:00:00.62 | Sce: Scene Ve:0 Fa:0 La:0
Saved: '/tmp/0028.png'
 Time: 00:00.67 (Saving: 00:00.04)

where frame 29 is elaborated but frame 28 is saved.

**System Information** Linux Ubuntu 16.04, Intel integrated graphics card **Blender Version** Broken: at least from 2.76b to latest build **Short description of error** While rendering in the background from the command line a scene with a non-empty video sequencer, the jump parameter is ignored and the incorrect frames are rendered. **Exact steps for others to reproduce the error** Consider the attached bug.blend file [bug.blend](https://archive.blender.org/developer/F738889/bug.blend) and run in the terminal the command ``` blender -b bug.blend -a ``` Now all the 30 frames are correctly created. If, instead, the couple of commands ``` blender -b bug.blend -s 1 -j 2 -a blender -b bug.blend -s 2 -j 2 -a ``` is run, the wrong frames are generated. In particular, the second command generates the even-numbered frames but with the contents of the odd-numbered frames. Moreover, the terminal output highlights the inconsistency: ``` Fra:29 Mem:16.95M (0.00M, Peak 17.47M) | Time:00:00.58 | Remaining:00:00.00 | Mem:0.49M, Peak:0.87M | Scene, RenderLayer | Path Tracing Tile 132/135 Fra:29 Mem:16.89M (0.00M, Peak 17.47M) | Time:00:00.58 | Remaining:00:00.00 | Mem:0.43M, Peak:0.87M | Scene, RenderLayer | Path Tracing Tile 133/135 Fra:29 Mem:16.83M (0.00M, Peak 17.47M) | Time:00:00.58 | Remaining:00:00.00 | Mem:0.36M, Peak:0.87M | Scene, RenderLayer | Path Tracing Tile 134/135, Sample 3/10 Fra:29 Mem:16.77M (0.00M, Peak 17.47M) | Time:00:00.58 | Mem:0.30M, Peak:0.87M | Scene, RenderLayer | Path Tracing Tile 135/135 Fra:29 Mem:16.77M (0.00M, Peak 17.47M) | Time:00:00.58 | Mem:0.30M, Peak:0.87M | Scene, RenderLayer | Finished Fra:29 Mem:16.43M (0.00M, Peak 17.47M) | Time:00:00.58 | Sce: Scene Ve:0 Fa:0 La:0 Fra:29 Mem:34.25M (0.00M, Peak 44.14M) | Time:00:00.62 | Sce: Scene Ve:0 Fa:0 La:0 Fra:29 Mem:34.25M (0.00M, Peak 44.14M) | Time:00:00.62 | Sce: Scene Ve:0 Fa:0 La:0 Saved: '/tmp/0028.png' Time: 00:00.67 (Saving: 00:00.04) ``` where frame 29 is elaborated but frame 28 is saved.

Massimiliano Leoni commented

2017-08-29 15:43:20 +02:00

Changed status to: 'Open'

Massimiliano Leoni commented

2017-08-29 15:43:20 +02:00

Added subscriber: @massimiliano.leoni

Campbell Barton commented

2017-08-30 04:33:37 +02:00

Added subscriber: @ideasman42

Campbell Barton commented

2017-08-30 04:33:37 +02:00

This is a problem with using the same scene as a strip in your sequence.

Setting the start frame also offsets it's position in the sequencer.

I've made a patch to support this - D2815, although I'm not convinced the fix is a net gain.

For 2.8x it may be best to remove this ability, see: #52586

This is a problem with using the same scene as a strip in your sequence. Setting the start frame also offsets it's position in the sequencer. I've made a patch to support this - [D2815](https://archive.blender.org/developer/D2815), although I'm not convinced the fix is a net gain. For 2.8x it may be best to remove this ability, see: #52586

Massimiliano Leoni commented

2017-08-30 12:44:33 +02:00

Ok, so perhaps I am using the feature the wrong way? Suppose I want to superimpose a logo on a part of the strip. What I would do is to load the image on another channel of the VSE and use a transform to add it to the scene. Should I do it differently? Should I put everything into another scene? Maybe I can achieve the same with the compositor...

Another use case would be to stop the animation at some point to have an explanatory text appear, to later resume the animation. What's the correct way to do these things?

Ok, so perhaps I am using the feature the wrong way? Suppose I want to superimpose a logo on a part of the strip. What I would do is to load the image on another channel of the VSE and use a transform to add it to the scene. Should I do it differently? Should I put everything into another scene? Maybe I can achieve the same with the compositor... Another use case would be to stop the animation at some point to have an explanatory text appear, to later resume the animation. What's the correct way to do these things?

Campbell Barton commented

2017-08-30 12:47:48 +02:00

It's best to have a scene that's only for editing video - so you don't put the scene into its self (causing this bug).

Massimiliano Leoni commented

2017-08-30 13:59:10 +02:00

I can confirm that using another scene works as expected. Thanks for the advise, I also noticed that inputting the same scene in the VSE brings some inconveniences.

Campbell Barton commented

2017-08-31 06:33:40 +02:00

Closed as duplicate of #30663

Campbell Barton closed this issue

2017-08-31 06:33:40 +02:00

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Background rendering with frame jump and sequencer is broken #52583