1. shoot video at 720 50p (or 60 if you like 30fps result)
2. add the strip to the timeline
3. add a speed effect strip to the shot, turn off “stretch to input length”, set “multiply speed” to 2.0
4. drag the tail handle of the shot so that it runs at half it’s duration (dur/2)
5. strip is now all dark frames
6. duplicate the camera strip shot, move it up 1 layer
7. nudge it’s first frame handle 1 frame to the right then drag shot back to line up with lower shot
8. add another speed effect with “multiply speed” set to 2.0. This will all be light frames
9. line up the 2 shots to start at the same point
10. select both strips (meta each strip with its speed effect if you like) then add a Gamma Cross effect.
11. Gamma effect strip should have “Default Fade” turned of with a value of 0.3. It’s “Blend” opacity value should be 1.0

You can vary the mix between light and dark frames by altering the the Gamma Cross “Fade” value.

To check that all this works create a waveform window from the VSE window.

This first attempt follows the interpolate in between frames approach but since considering it further and the fundamental problems with this method and the fact that all the motion has been captured its exposure and color that need constructing. To make use of the potentially wider dynamic range the output its assumed a bit depth greater than 8bit is required and possible as seen in a recent post.

But the following is a Interframe based method for now.

Really following on from my last post regarding 16bit Scene referred linear .EXR’s and 10bit lossless 4:4:4 h264 from video shooting Canon DSLR’s.

First some files as to where I’m at:

Basic output 1920×1088 8bit 4:2:0 h264 file: [Save As]

http://www.yellowspace.webspace.virginmedia.com/merge.mp4

A 16bit .tif frame:

http://www.yellowspace.webspace.virginmedia.com/IM-hdr_000000.tif>

A 16bit linear light .exr frame:

http://www.yellowspace.webspace.virginmedia.com/IM-hdr_000000.exr>

The process and tools is basically the same as here:

8bit Video to 16bit Scene Referred Linear .EXR’s>

With the addition of a great frame doubling/interpolation tool called Interframe for AVISynth:

http://www.spirton.com/interframe/>

And as always the excellent support from the Doom9 community.

http://forum.doom9.org>

Particularly -Vit- (QTGMC) & cretindesalpes (Dither Tools). The Interframe referencing lines in the script below is courtesy of -Vit- word for word, although not his tool . Disclaimer this does not negate the need to read the Interframe documentation.

So using the sample Canon MOV file provided by the RedKiteMedia, log in to download native file:

http://vimeo.com/33987353>

And this script, which is work in progress and needs work.

LoadPlugin(“c:\Program Files\AviSynth 2.5\plugins\mvtools2.dll”)

Dither_convey_yuv4xxp16_on_yvxx()

There are things to tidy up in the script, such as a reverse rec709 curve to linearise as per previous .EXR workflow rather than the sRGB 0.45 ‘degamma’ in the script.

Although blending is done linear light and creating a 16bit output, there’s room for a lot of improvement. I question the ‘merge” method compared to enfuse or Tufuse, but kind of feel this is more a LCE / Local Adaptiation process rather than a ‘traditional’ HDR one. HDR from only two exposures?, not really. Compared to a bracketed set. Where as Local Adaptation / Local Contrast Enhancement may provide more natural results, scroll down to the “Concept:Tonal Hierarchy and Image Contrast” here:

http://www.cambridgeincolour.com/tutorials/high-dynamic-range.htm

A way of merging the two luma planes into one 16bit levels range and whether to merge both chroma or just one from decent exposure, haven’t bothered with audio currently either.

Save the script as an .avs and then use AVS2yuv or AVS2pipemod along with a 10bit build of x264 or a 16bit hdri build of Imagemagick depending on output required. All as per previous post:

8bit Video to 16bit Scene Referred Linear .EXR’s>

Although I’ve loaded the latest Magic Lantern Firmware still haven’t had chance to test it yet. Awesome work by the Magic Lantern Team.

I had the artist (my daughter) create a story and artwork, that we placed up on a copy stand (the cupboard door). With the camera locked off we proceeded to animate the scenes and characters. Some shots were cutaways others were sequences. By the end of the shoot we had a 20-30 shots.

I wanted to load them all up as individual strips in the VSE as they needed to be different lengths, none would run 1fps as in typical Blender animation sequences. But when I select a range of images in the folder of course that is what Blender does. It joins all the frames up as a sequence, running at 1 frame per second.

I tried seperating the frame sequence strip into frames but then each shot was just 1 frame long. I really needed a arbitary duration of a couple seconds that I could trim to length if neccassary, as stretching just a single frame strip is fiddily and tedious.

My answer at the time was to drag in each shot individualy, then they get to be a couple seconds each.

Recently I noticed an interesting factoid from Sago on a thread at BA http://blenderartists.org/forum/showthread.php?236351-Since-2.59-Separate-Images-in-VSE-no-longer-asks-for-Length

When you seperate a strip into individual frames using the Y key (or menu) there is a Tweak Last value to alter the resulting strip durations. BUT it isn’t shown in the VSE, you have to look in the 3D view tool shelf, right down the bottom!

http://wiki.blender.org/index.php/User:NeXyon/GSoC2011/Proposals

And here is the development blog to see what happened:

http://audaspace.wordpress.com/2011/08/25/gsoc-2011-wrap-up/

Fortunately some of this development spilled over into Blender’s VSE too. there are some really useful tools now, like

waveforms on strips

a working f-curve fade effect

You can also change the pitch of an audio strip, which is good for changing audio length to match video with different frame rate. Or you can f-curve the pitch change over time (weird but cool).

And somewhere in there is shelving for high and low frequencies.

Now it’s no Digital Audio workstation (DAW) but at least the VSE has the basics for video assembly built in now. And while Blendervse suggests a more robust workflow (rightly so for quality), of rendering vision from Blender and muxing (joining video and audio) externally. I often need quick and dirty renders of synced effects or videos. So muxing a file in Blender is a necessity.

The one issue I have had with this was a simple corruption of a project that I was working on. At some point the Scene settings for Audio were changed to a null (illegal) value, which killed ffmeg at render time and crashed Blender.

So I suggest that you make sure that Properties > Scene settings > Audio is set to Stereo or Mono before rendering (you can use multitrack too if you use the right output codec).

Properties > Scene > Audio settings

To take advantage of the new Panning effect, that you can apply to a strip (via strip properties), you must ensure that the audio is mono first.

To do that you have to go to Outliner then change Display mode button to Datablocks. Scroll down till you find Sounds. Expand the sound you want and set it to Mono.

datablocks > audio > mono” width=”496″ height=”624″ />

By the way, this is not just 8bit in a 16bit file, type of conversion, shoe box in a steamer trunk analogy and the usual “no point all you get is bigger file sizes”, this method generates additional data.

It works by denoising the source and with the LSB (Least Significant Bit) data of each frame and stacks it with the MSB (Most Significant Bit), the extra data bolstering each image frame and giving more data to grade with and option to dither with an encoder friendly dithering method to reduce the risk of banding.

http://en.wikipedia.org/wiki/Bit_plane

Here’s a link to a 8bit & 16bit version of the same frame from a Canon MOV 1920×1088 source.

Samples.zip

Welcome comments if you can see a degrading of the image by stacking LSB/MSB .

Please test them with a grade and as you manipulate them check the histograms for combing, compare the performance of the 8bit against the 16bit, whether you feel there’s any point in generating bigger files for the added ‘gradeability’ is your choice, but hard disk space is cheap.

Direct import of the MOV into Blenders 32bit float Compositing Nodes and float data in the VSE fared no better than the 8bit source in the samples above where as the 16bit stood up to more processing. 32bit float processing of 8bit sources in Blender is not enough to prevent combing of the 8bit source.

The process set out below assumes the video sources are encoded based on a Rec601 or Rec709 transfer curve, the process outlined below uses an inverse Rec601/Rec709 curve to linearise the source rather than using the inverse of a typical sRGB 0.45. Which does not create a true scene linear output for video sources they weren’t gamma encoded with sRGB curve to start with but a Rec601/709.

So there should be no squeezing of shadow detail by inverting the wrong gamma curve. ‘Scene’ referred linear rather than treating as a ‘Display’ referred source. This is nothing to do with ‘crushing blacks’ from an incorrect color space conversion to RGB by scaling luma.

Prerequisites:

Avisynth 2.5.x (2.5.8 currently)

http://sourceforge.net/projects/avisynth2/files/

FFmpegSource2 plugin (Don’t use 2.16 it’s buggy for full range luma sources)

FFMS2-2.1.5

AVS2yuv.exe

http://akuvian.org/src/avisynth/avs2yuv/

Imagemagick Q16 or hdri compiled options.

If your on Linux doing all this with Wine then then AVS2yuv will happily pipe data to a Linux build of Imagemagick.

http://www.imagemagick.org

x264 10bit [JEEB Patched]

http://x264.fushizen.eu

Grab the 32bit or 64bit 10bit build from top of thread.

AVSPmod, Virtualdub or Favourite Text Editor.
(You may have problems with AVSPmod 2.2.0 version, try 2.1.8 if thats the case.)

http://forum.doom9.org

Dither Plugin

http://ldesoras.free.fr/src/dither-1.13.2.zip

dfttest Plugin

http://web.missouri.edu/~kes25c/dfttestv18.zip

Masktools2 version a48 or above

http://manao4.free.fr/masktools-v2.0a48.zip

Process:

Install Avisynth.

Copy various plugin zips to Avisynths plugins folder in Program Files\Avisynth 2.5\ unzip them to folders, then copy out the .dll’s and .avsi’s directly into Avisynths plugins folder, this simplifies paths to various plugins when writing scripts.

Install Imagemagick Q16 / hdri. Open a console or cmd and type identify -version. Hopefully you’ll see something similar to:

Version: ImageMagick 6.7.0-8 2011-06-26 Q16 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2011 ImageMagick Studio LLC
Features: OpenMP HDRI

To get up and running create a folder and put x264.exe, AVS2yuv.exe and your test movie file into it.

Everything that follows assumes Canon HDSLR h264AVC 1920×1088 source. Edit scripts to suit source if it differs. If you’re importing 4:3 PAR sources you may wish to resize to 1:1 PAR within the scripts below. For HDV 1440×1080 source add the line:

Dither_resize16 (1920, 1080, 0, 0, 1440, 1080, "spline36", cplace="mpeg2")

after Dither_Convert_8_to_16 () and ensure that when using the AVS2yuv command lines that you amend –input-res and/or -size accordingly. ie: 1920×1080

Open AVSPmod or your favourite text editor and create to .avs scripts suitably named. Strongly suggest AVSPmod, or Virtualdub.

This script for RGB output to go to Imagemagick for image sequences:

LoadPlugin("c:\Program Files\AviSynth 2.5\plugins\ffms2.dll")
LoadPlugin("c:\Program Files\AviSynth 2.5\plugins\mt_masktools-25.dll")
FFmpegSource2("MVI_0000.MOV")
Dither_convert_8_to_16 ()
#Dither_convert_yuv_to_rgb(matrix="601", tv_range=false, cplace="MPEG2", chromak="bicubic", lsb_in=true, output="rgb48y")
#Dither_y_gamma_to_linear (tv_range_in=false, tv_range_out=false, curve="709")
#Dither_convey_rgb48_on_yv12 (SelectEvery (3, 0),SelectEvery (3, 1),SelectEvery (3, 2) )
DitherPost()

And 2nd script to go to 10bit Lossless x264:

LoadPlugin("c:\Program Files\AviSynth 2.5\plugins\ffms2.dll")
LoadPlugin("c:\Program Files\AviSynth 2.5\plugins\mt_masktools-25.dll")
FFmpegSource2("MVI_0000.MOV")
Dither_convert_8_to_16 ()
#Dither_convey_yuv4xxp16_on_yvxx()
DitherPost()

Open and preview your first script in AVSPmod or Virtualdub to test that the basics are in place. You should simply see the first frame of your video. Then do the same with your second script and test that.

You may get an error message about certain plugins having ‘_’ underscores rather than ‘-’ hyphens, but really just make sure your Avisynth plugins name and the names and locations in the script pointing to them match.

If all is working, we can move onto AVS2yuv.

Unfortunately neither Virtualdub or AVSPmod can export 16bit data from within Avisynth, luckily AVS2yuv or AVS2pipe (which includes audio) can pipe the 16bit data to an external application like Imagemagick and a 10bit build of x264.

So to get the 10bit or 16bit data out we first have to unhash the #Dither… lines from our scripts and resave them. You’ll need to add a hash in front of the DitherPost() entry. DitherPost() takes the 16bit data back to 8bit. We needed that line active so we could preview in Virtualdub or AVSPmod.

Once the scripts are tweaked test them out by opening a console, cd’ing to the folder you created holding the scripts, source file, encoder etc and enter this (assumes Linux, if on Windows remove the wine bit) into the console for linear .exr’s:

wine ./avs2yuv.exe -raw "script_Lin_RGB.avs" -o - | convert -depth 16 -size 1920x1088 -set colorspace RGB -colorspace RGB rgb:- "output_%06d.exr"

If you get out of memory errors try this on the CLI:

identify -list resource

Which will show you how much resources Imagemagick considers available. For example you may have 3GB memory and 6GB map. Imagemagick can be limited to use only so much RAM and the rest of the video data cached in /tmp (on Linux)

To limit resources available to Imagemagick add -limit memory 1GiB -limit map 2GiB in between:

convert and -depth

Change the GiB or MiB values above to fall within the resources listed by Imagemagick for your hardware.

For 10bit Lossless h264:

wine ./avs2yuv.exe -raw "script_YCC.avs" -o - | ./x264-64-10bit.exe - --demuxer raw --input-depth 16 --input-res 1920x1088 --fps 25 --fullrange on --preset ultrafast --qp 0 --output "10bitOutput.mp4"

Obviously adjust input-res to suit your source. Assuming 1920×1088. You might prefer .avi or .mkv as your output container rather than mp4.

If you prefer sRGB gamma 16bit .tif’s then hash out the Dither-y-gamma…… line from the RGB script and change the Imagemagick line to .tif rather than .exr or if you would prefer linear light .tif’s or .pngs for example you can embed an icc profile into your file with imagemagick by adding -profile NameOfYourICC.icc to the Imagemagick route on the CLI. I add the -profile whatever.icc before the -set colorspace stuff.

If you need a linear light sRGB ICC profile for any color managed application (that uses ICC’s) including After Effects 7.0 upwards then you can get them here on Stu Maschwitz awesome blog: http://prolost.com/blog/2006/2/7/linear-color-workflow-in-ae7-part-1.html and direct link to icc zip file here: LinearProfiles.zip

Just unzip and drop the ICC you want to use into the same location as the avs script & source video files. Make sure the filename in the CLI call is the same as the ICC file name. I always take an additional step of removing any spaces from the file name and/or replacing the spaces with underscores as this is the CLI and spaces can trip it all up.

I intend making this process a bit easier via AVSPmod python macros, but for now to get up and running.

This is really the basics, there are many functions available within Avisynth to include in our scripts, many now at 16bit precision including gamma aware resizing, noise reduction, color correction, adding grain as well as hundreds of 8bit functions including sharpening, optical flow based slow motion, deinterlacing, upsampling, the list goes on.

Let me know how you get on and if there’s anything specific you’re after. I’m going to look at batch conversion python script for AVSPmod next.

Anyway I made a linear grad image that filled the screen, and placed the bmp on the timeline. You will notice on the waveform and histogram that the blend is not exactly linear (perhaps a different colour space?) but it is our baseline.

Then I added a number of Adjustment layer effects that change only a specific wheel. In each case I crushed the value to black. The first was the Darks on the left most wheel. Below you can see that the effect from this wheel terminates around 25% of the waveform scale and it affects the ramp back up to white (on the right), so it has a long fall off.

Next I crushed only the mids, but as there is no slope or Q point value, you cannot alter the amount of fall off around it. Therefore all the image is greatly affected as there is dramatic fall off all the way to the edges.

And finally I crushed the Brights as well. The result is the same, a gross overall affect. Where the whole image is darkened but that is to be expected as the toe or dark part of the image is already black. But what if I raise the Brights to 2.00…

Now we can a similar fall off from 25%, but this time 75% of the image is blown out or at the top of the curve. So it has a short fall off, the inverse of the black wheel.

All this means that corrections with these wheels cannot be targeted as they are in the comp nodes, when using the curve node. In other software the transition between these wheels Dark-mid, mid-bright can be modified, but this isn’t available with Strip properties at the moment. And if you try the same modifications using the color balance node the results differ a lot. The change point is more predictable and you can achieve better contrast. But the processing is slower. It would be great to have access to the colour tools from Comp Nodes in the VSE strip properties.

I added a bit of opacity noise too, just for good measure. I did have to change the strip’s blend type (at the top of the properties panel) to Replace, for the opacity to take effect. I guess you could apply the colour correction switch usefully to footage that has a alternate frame beat, say with flickering florescent lights, careful modification of the period using cycles modifier could help.

Have a play and show us how crazy you can get animating weird values!

The biggest drawback to this proxy implementation (at the moment) is that it forces the user to switch every clip individually back to hires! Imagine doing that to a hundred shots. It would be handy to have a global effect. I tried setting my source clips up as Source scenes (see earlier post) then cutting with those scenes in a master scene VSE. Hoping that they could be switched as a group. But they bog down upon playback, as the Source scene pre-renders the strip before use in the master scene. And anyway you still have discreet clips to switch in that scene too.

Rant Alert:

And another thing about using Source scenes, at the moment I am noticing that Blender Syncs and plays all scenes back at the same time, even if you aren’t asking that scene to playback in the current Master scene! So there is all this extraneous noise coming from unused scenes, even though they aren’t sync locked for playback, aaarrrrgggh!

Rant off.

Transform Strips.

They perform top down changes to anything below on the timeline (would be cool to have audio versions too!).

In my example I have recorded a clip with the Technicolor cinestyle setting in my camera. This produces a flat non-contrasty look. First up I make a transform strip that has the colour tool active and stretch the pedestal or black point back down to zero, and I give the mids a small push. The Blender colour tool doesnto specify dark,mid,bright cross over as yet so making a log LUT is really guess work and eyeballing. So “use the scope Luke, use the scope”, don’t trust the force. As Han Solo says,  ”Hokey religions Codecs and ancient weapons workflows are no match for a good scope at your side, kid.”

I have saved this Transform Strip “Look” along with another warmer “Look” in another scene. I guess I could have stuck some reference images beneath them too, so that I could browse the effect that I wanted before copying it out to the other Master scene.

You can slide this Transform strip anywhere along the timeline or stretch it out to cover all of the clips you have edited. My system performs in realtime (with proxies) using one active Transform strip, but stacking them up slows it all down a bit to much.

To make a different “Look” I have duplicated the basic black stretch fix and modified the colour tool settings. You can play with the mix type and saturation too.

http://lists.blender.org/pipermail/bf-committers/2011-May/032152.html

The implementation:
* currently, proxy building (in background) and "Record run" indices are
   implemented, other time code indices following later.

   To use them: build the branch (see above), open a movie file, go to
   N-keys panel "Proxies", check "Use Proxy", by default 25% proxies are
   the only one build, but you can change that (or build no proxy at all
   and use timecode indices only).

   Do that for as much movie clips as you like.

   Select all of them.

   Go to "Strip -> Rebuild proxy"

   On the status bar, there should be a progress bar (which currently shows
   per file progress, total progress is TODO).

   Blender is building proxies in the background, so you can continue
   working.

   After the build process finishes, you can select different time codes
   (currently only "record run" is implemented)
   and use the Proxy preview (N-keys dialog in preview window) again.

* seeking works perfectly for the first time in blender (no stuttering,
   failing completely on broken files, etc.) since with indices, the
   system now works completely PTS based. And: the preseek heuristics isn't
   needed anymore, so blender will always seek to the right I-Frame, which
   means: faster feedback on CPU-heavy footage (like Sony EX3) e.g.!

* currently missing:
   * other timecode tracks than "record run".
     In case you don't know: "record run" means: use the frames as they
     are recorded, ignore gaps, if someone hits the stop button on the
     camcorder.

     "free run" means: use a global time counter (configurable on the
     camcorder), if someone hits stop, consider those frames, and display
     them as black gaps, frozen pictures.

     "free run (interpolated)" means: if your camcorder is too cheap,
     use record time/date to simulate a real "free run"-mode, usually only
     found in prosumer camcorders.

   * proper variable frame rate support (could be considered as some sort
     of "free run", since the idea has a lot of similarities.

   * audio code doesn't use the same seeking code path, leading to A/V sync
     problems.

The implementation is very similar to 2.4x Blender from a GUI perspective. Added benefit of Timecode with this new version. This is however Work in Progress and in a separate branch for testing and feedback purposes.

Screen grab.

The 2.4x implementation was a bit of a pain, multiple sequence strips could not be selected and proxy build settings applied, each movie strip had to be selected individually and a tick box  ‘Use Proxy’ activated (this remains the process), followed by individual ‘Rebuild Proxies’ menu option invoked for each strip in turn. Not a lot has changed with regard to this process other than the ability to rebuild all proxies by selecting the menu item once.

From a user perspective:

It’s not unusual to be working with 100+ video clips from a day shoot, perhaps 500+ for a week, especially with cameras such as HDSLR’s and limited record time’s per file, although there is good reasons to capture many short clips than excessively long ones even when capturing to tape. Depends on nature of project however, with regard to live performances for example.

With that in mind, the current implementation suffers the same problems as 2.4x.

Currently selecting all movie strips and toggling proxies on, setting ‘Build Size’, ‘Quality’ and ‘Timecode’ choice does not work. Activating proxies only works by selecting each strip individually. Settings from the previous strip don’t remain for the next strip so each strip adopts default settings, which appear to be fixed, not savable or accessible in ‘User Settings’ at the current time.

After highlighting each strip and toggling proxies on. They do not build until invoking ‘Rebuild Proxies’ from the ‘Strip’ menu. The build process doesn’t appear to prioritise strip order to build from, for example starting with the strip the play head is over, stands a good chance that’s where the user is going to play from? Then perhaps work back each way from the playhead.

Bugs:

I’ve built FFmpeg from GIT, to /usr/local and then compiled Blender as per main branch. Ubuntu Natty Narwal 64bit.

I can not get a preview in Blenders VSE preview window when proxies are chosen over ‘No Proxy, full render’ I see a black screen and light grey dashed frame outline as screen grab above. I assume this is easily fixed and very possibly a problem related to my build / compile options.

Trying to activate proxies for an image and image sequences crashes Blender outright when invoking the ‘Rebuild Proxies’ menu option.

Suggestions:

Considering there is no hardware acceleration for video playback in Blender and the only option to play HD sources in real time is via proxies, the current implementation is painful, as it was in 2.4x. Selecting each file in turn, having already selected them once in the process of getting them on the time line is unhelpful and it wouldn’t be unreasonable to expect that if Proxies are required for one HD file then they’re going to be needed for all HD video files in a project? What would help are options like:

• ‘Use proxies’ for this project tick box. Then every movie clip / image sequence over a certain resolution would immediately build proxies when added to the time line.

• A ‘Build Proxies’ for all movie / image files in this directory tick box in Blenders file manager, including a tick box to include sub folders.

• Multiple sequence strip selection and activation of proxies including the transfer of settings from one strip to others.

• Buttons on the time line N key panel for ‘Rebuild Current Strip Selection’ & ‘Rebuild All’. maybe hot keys mapped eventually.

• Perhaps a separate GUI to batch proxy creation in advance, personally I’d rather set them up in advance, as I do now than mess around on the timeline, unsure which strips have proxies built, which are building, which need to be built. Perhaps a sequence strip could be colour coded or ‘Proxy Built’ stamped on it, to show strip proxy status / progress.

Kdenlive has recently had a Proxy workflow added and works well. There are also plenty of options for proxy generation.

Whilst mentioning Kdenlive, MLT the underlying Media Lovin Toolkit based on FFmpeg + Jack + Frei0r + SDL, is cross platform, Windows/Mac/Linux and it must be facing the same problems with playback, indexing, colour space, audio etc. Do kind of wonder sometimes just how many ‘Reinventions of the Wheel’ are needed and if Blender could benefit from such a maturing application as a basis for all media handling including capture and Blackmagic SDI / HDMI duties.

http://www.mltframework.org/twiki/bin/view/MLT/

Please feel free to add your own comments.

**UPDATE** 5th July 2011

Ok, a few comments based on latest ffmpeg and blender-vse-proxies from git.

My previous tests were with h264AVC from a Canon HD DSLR which gave me a black screen for playback of proxies. On further investigation proxies generated from this source are been written with a frame rate of 50000, yes 50000fps. So no wonder there’s problems . Other formats work fine, like HDV, DV and even 10bit h264 HD 1920×1088 from the same 8bit h264AVC source. But the proxies generated from the 10bit source have a frame rate of 50fps even though both Blender Output settings is 25fps and the original source is identified as 25fps, when played back by ffplay for example.

Other stuff:

Concluded could really do with a 100% Resolution proxy option, sounds odd but HD 100% MJPEG vs 100% h264AVC, MJPEG is substantially less demanding on resources.

The N key options for percentage proxy playback in the preview window are flawed, when mixing media, even at same source resolution, some need a lower proxy resolution than others, so building one strip with 25% and another with 50% and having proxy preview set to 50%, means the 25% strip plays back black.

So we either have to generate all proxies at same proxy percentage regardless, or at multiple proxy values. ie 25% 50% 75% ’100%’ (hopefully , the former could simply be a project wide setting or selected in Blenders File Manager (as mentioned previously) generating a proxy file on import at chosen 25 50 75 100% based on source file resolution.

Then have Blender automatically select the highest resolution proxies previously generated for playback, if the user finds playback sluggish on any particular strip, then a slider 25 50 75 100% Proxy Preview ‘override’ and automatic rebuild of that strips proxy to the new resolution. Users would soon learn what proxy for what source their hardware can handle.

Then all that would be required is a simple ‘Proxies ON/OFF’ tick box in the N key panel of the Preview window rather than 25% 50% etc or better still in the Preview Window Header, opening and closing the N key panels to fiddle with proxy playback settings is a bit unfriendly.

If the Preview Window is then set to ‘Proxies ON’ and no proxies exist then a black screen for that strip, it’ll be soon apparent to the user why.

Next peculiarity, if proxies have already been generated for a strip, say at 25% and you select proxy playback in the Preview window at 25% playback, Blender uses proxies regardless as to whether the strip properties in the N key panel has Proxy / Timecode ticked or not.

Now what happens when adding a couple of clips? Select them in the file manager, add them to the timeline, both highlighted, Tick ‘Proxy / Timecode’, tick 50% resolution, then go to ‘Strip’ menu to find ‘Rebuild Proxies’ (Please a button in the N key panel. ) Watch progress bar, even though both strips are ‘selected’ only the ‘selected’ and ‘highlighted’ strip gets a proxy built. Currently each strip has to have proxies ticked, quality and resolution settings individually before rebuilding from the ‘Strip’ menu. Then and only then will all ‘Proxy / Timecode’ ticked boxes rebuild.

Adding any image to the timeline, png, jpg, hdr whatever, then selecting proxy resolution required then hitting rebuild proxies crashes blender outright.

Problem:

I wish that I could re-use Colour Corrections across many clips. And I want to change correction in the middle of a clip!

Solution:

Well, you can change the colour wheels of any strip…

… and it doesn’t have to be the Video Strip you want to change! If you add a Video strip (or scene strip)to the timeline then add a Transform Strip to that you will find that you can change the colour correction by proxy. What do I mean by that? You have created a modifier for the video strip, normally that modifier is used to change the size or cropping of the source material, but in this case we can apply a colour correction instead.

And not just one colour correction but many! You can stack another Transform Strip by Adding it (shift-A / effect / transform) to the original video strip. Blender will place it above the first Transform Strip. You can then make adjustments to the original footage or you could make additional changes to the first Transform Strip by adding the extra Transform strip to that one.

2 Transform Effects added to a video strip

Great you say now I have a couple of Transform effects setup that fix exposure changes over a shot, but how do I get from one to the other?

Solution part 2:

Blender lets you add a Cross (or Dissolve) strip between almost anything! So you would select the 2 Transform Clips that you just made and add a Cross effect. But that just mixes from the start to the end, what good is that? Well it doesn’t have to be that way. If you select the Cross Strip in the VSE and press N for Properties you will see in the sidebar a menu called Effect Strip. It lists the 2 sources for the effect and a button labelled Default Fade. Untick Default Fade!

Untick default fade for mixing madness!

There you go, you now have access to a keyframeable value. You can park at any point on the Cross Strip and specify an amount of mix between the 2 Colour Corrections. Then you can tailor the  speed of mixing in the f-curve editor.

*Extra points for anyone who can simulate a flikering light with a Curve modifier

Hey, what about re-using the colour correction!? Well..
-select the Transform Effect that you want to re-use and duplicate it. It should attach to the mouse so you can drag it up a track. It is still assigned to the original Video or Scene Strip however.

-Next select the other video strip you want to apply the effect to and shift select (add to selection) the duplicated Transform effect.

-Goto the Strip menu at the bottom of the VSE and select Reassign Inputs (or press the r-key).

Like magic the tranform effect will jump to the new clip. I know it isn’t easy like drag-n-drop but it will do for now.

If that wasn’t very clear try the video version at the top of the page.