Earth Notes: OpenTRV Movie Mashup 1: Video Out-takes and The Rest!Updated 2021-03-18 21:12 GMT.
By Damon Hart-Davis.
This is an Earth Notes mini video podcast episode for 9th November 2019.Here are a few [OpenTRV] out-takes from yesteryear that I like but might otherwise never see the light of day. Thanks to Mark, Dennis and Victor for their cameos!
Turn the mechanical value to fully on, usually shown by a number 5, by turning the top of the TRV all the way open.
This means that you can then unscrew the base of the TRV right here, nice and easy, with just your fingers...
[0m51s, Victor channelling Radbot]
I learn what times of the day you are at home ...
... keeping you comfortable, and saving you money, while you get on with the things that really matter.
[1m07s, Mark and Damon from Green Challenge clips]
Psssssssssht, beep! Amsterdam, we have a problem!
People want to stay warm and reduce carbon emissions...
... and their energy use at the same time. But how?
[1m17s, Mark captioned "FUEL POOR"]
I'm cold, and I want to turn on my heating. But I can't afford to.
[1m21s, Damon captioned "SCIENTIST" and holding ballons]
Here's the EU carbon emissions. 20% is from heating the home.
[1m25s, Mark captioned "SUIT"]
So, Damon, why OpenTRV?
[1m29s, Damon captioned "SUIT"]
Mark, it's a small chunk of money to save a large chunk of carbon!
[1m36s, Damon with many beards]
There's more on my "Earth Notes" Web site at Earth.Org.UK.
Yes, I confess, I was working on my iMovie skills with this. I'm hoping to put together another small video podcast episode soon. It will be something of a teaser, I hope!
Possible production pipeline
Even for less than 2 minutes' 960x540 output (with quite a lot of highly-compressible near-stills and removed audio) iMovie spat out MP4s of ~80MB, 63MB and 33MB for it's high/medium/low 'quality' outputs. (The 'pro-res' .mov, still possibly lossily-compressed unlike the FLAC for my audio episodes, was ~640MB!)
% ls -al img/video/OpenTRV/OpenTRV-mashup-1* 80437196 img/video/OpenTRV/OpenTRV-mashup-1.hifi.mp4 63464687 img/video/OpenTRV/OpenTRV-mashup-1.mp4 32542263 img/video/OpenTRV/OpenTRV-mashup-1.mp4L
avconv scripts that I already use to make smaller versions of the movies seem to be able to squeeze a lot of bytes out without too many artefacts, eg see the 800x450 version below at ~4MB more than an order of magnitude smaller than the 'medium' iMovie output. The reduction in pixel count is not responsible for much of that. The good, slow, codec is.
% ls -al img/a/v/OpenTRV-mashup-1.mp4* 2909342 img/a/v/OpenTRV-mashup-1.640x360.mp4 991111 img/a/v/OpenTRV-mashup-1.640x360.mp4L 3851067 img/a/v/OpenTRV-mashup-1.800x450.mp4 1257108 img/a/v/OpenTRV-mashup-1.800x450.mp4L
To have something that could be remastered, lossless would be good. I'm not sure that I even get that with the
.mov but in any case I can't spend 300MByte+/minute on the off-chance! Maybe capturing the 'high' or 'medium' output for archival is reasonable.
For this video episode I have used the medium output as the media that will go end users via the RSS feed. (Web site visitors get the much smaller 800px and 640px width versions in the video player in the page already.)
So, maybe the right thing to do is capture the 'high' version as '
.hifi.mp4' for archival, and manually create a version for RSS that has had one pass through
avconv to take out an order of magnitude in size. This new version could/should be assessed for acceptability. I now show the
file as the archival/'original'/low-loss version automatically under each viewer. Or this transformation can be done in place of a copy/link if the space saving is significant, but the RSS mechanism will need to know how to locate and publish it.
It may still be better for fidelity (ie reducing artefacts) in the scaled and low-fi versions if they work from the highest-fi copy directly.
Here is the
mediainfo dump for the medium iMovie output:
% mediainfo img/video/OpenTRV/OpenTRV-mashup-1.mp4 General Complete name : img/video/OpenTRV/OpenTRV-mashup-1.mp4 Format : MPEG-4 Format profile : Base Media / Version 2 Codec ID : mp42 (isom/mp41/mp42) File size : 60.5 MiB Duration : 1 min 46 s Overall bit rate mode : Variable Overall bit rate : 4 790 kb/s Movie name : OpenTRV mashup 1 Movie_More : OpenTRV clips and out-takes! Encoded date : UTC 2019-11-09 18:18:49 Tagged date : UTC 2019-11-09 18:21:12 Video ID : 2 Format : AVC Format/Info : Advanced Video Codec Format profile : High@L3.1 Format settings : CABAC / 2 Ref Frames Format settings, CABAC : Yes Format settings, ReFrames : 2 frames Format settings, GOP : M=1, N=30 Codec ID : avc1 Codec ID/Info : Advanced Video Coding Duration : 1 min 46 s Bit rate mode : Variable Bit rate : 4 681 kb/s Maximum bit rate : 768 kb/s Width : 960 pixels Height : 540 pixels Display aspect ratio : 16:9 Frame rate mode : Constant Frame rate : 29.970 (30000/1001) FPS Color space : YUV Chroma subsampling : 4:2:0 Bit depth : 8 bits Scan type : Progressive Bits/(Pixel*Frame) : 0.301 Stream size : 59.2 MiB (98%) Title : Core Media Video Encoded date : UTC 2019-11-09 18:18:49 Tagged date : UTC 2019-11-09 18:21:12 Color range : Limited Color primaries : BT.709 Transfer characteristics : BT.709 Matrix coefficients : BT.709 Audio ID : 1 Format : AAC Format/Info : Advanced Audio Codec Format profile : LC Codec ID : mp4a-40-2 Duration : 1 min 46 s Source duration : 1 min 46 s Bit rate mode : Constant Bit rate : 103 kb/s Nominal bit rate : 128 kb/s Channel(s) : 2 channels Channel positions : Front: L R Sampling rate : 48.0 kHz Frame rate : 46.875 FPS (1024 SPF) Compression mode : Lossy Stream size : 1.30 MiB (2%) Source stream size : 1.30 MiB (2%) Title : Core Media Audio Language : English Encoded date : UTC 2019-11-09 18:18:49 Tagged date : UTC 2019-11-09 18:21:12