Earth Notes: OpenTRV Movie Mashup

106s "OpenTRV mashup [VIDEO]" (poster) (captions) Uploaded . Downloads:

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!

[00:20, Damon]

I'm Damon.

[00:21, Mark]

I'm Mark.

[00:31, Dennis]

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...

[00:51, 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.

[01:07, Mark and Damon from Green Challenge clips]

Psssssssssht, beep! Amsterdam, we have a problem!

[01:12, Mark]

People want to stay warm and reduce carbon emissions...

[01:14, Damon]

... and their energy use at the same time. But how?

[01:17, Mark captioned "FUEL POOR"]

I'm cold, and I want to turn on my heating. But I can't afford to.

[01:21, Damon captioned "SCIENTIST" and holding balloons]

Here's the EU carbon emissions. 20% is from heating the home.

[01:25, Mark captioned "SUIT"]

So, Damon, why OpenTRV?

[01:29, Damon captioned "SUIT"]

Mark, it's a small chunk of money to save a large chunk of carbon!

[01:36, 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!

(A mid-pandemic virtual meetup was in fact the next video podcast!)

All these clips were created in the UK, or at least for us in the UK!

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

The 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 .hifi.X 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
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

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

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