It’s been a slow start to the productive part of my mini residency at DINA, partly due to being distracted by other potentials of the building and also people calling in to see me. All intended outcomes, but distracting from the additional technical elements I originally wanted to look at.
Because of my dissatisfaction with the image quality of the cheap media players I had bought, I decided to reconfigure a Raspberry Pi to do the job. I have used these to play back Full HD video brfore, but not a folder full of separate files. Below is the Bash script, but I’m not going to take it apart too much as all the bits are cannibalised from other peoples’ work (links & credits provided).
I have a few first-generation Raspberry Pi Model Bs and Omxplayer gives very satisfactory playback of Full HD video. I found a basic script for playing back a seamless loop of videos in a folder on Application Server.
This works fine, but I needed a few other bells and whistles to make it installation-friendly, namely auto-login, auto-start and auto-shutdown. In my experience, Raspis are very resilient and will tolerate a hard shutdown (pulling the plug), but that is neither big nor clever, and it would be better to shut them down properly before powering off.
The auto-login and auto-start was found on Open Tech Guides.
The shutdown was enabled using cron / crontab, scheduling a shutdown at a specified time of day (link here), although this led to one of the limitations of the Raspberry Pi, it has no internal clock so it doesn’t know what time it is except in relation to when it was powered on or if you manually set the time. I bought a Mopi power management module, but I haven’t used that yet, preferring this time to use a wifi dongle in order to retrieve the time from the internet.
I found instructions to do this at the command-line here, and it was pretty easy once I started using the correct password. It refused to work on the unpowered USB hub I was using. Two USB sockets on the old models is not enough.
Note: I could have saved myself some time and got this blog post finished a lot sooner if I hadn’t forgotten to clone the first working version I made of this on Raspbian. Duh! Here is a link to do this at the command-line on Mac. I also found a very promising app called PiCloner for Mac OS X, but it refuses to launch on my first-generation Macbook running 10.6.8.
I also decided to add the ability to access the files from an external USB thumb drive. This makes the Raspis much more installation-friendly as you can just substitute a new or alternative playlist on an other drive. I found instructions on mapping a drive to a path on instructables.com. I made each portion of the videos as separate files that all fade in from black and fade out to black. The playback is seamless on black with no glitching but I haven’t tried to make a seamless loop yet.
The only problem I had with the script was that I had given the files long names with spaces and this seemed to cause a problem with the script I used. It might be that the is something that can be finessed to support long filenames. In the meantime, I just renamed them to be eight characters or less with no spaces and I used numeric filenames to force the playback order e.g. “010.mov”, “020.mov”, “021.mov” etc, and duplicated the video files of the credit slides and renamed them to play in the order I wanted them to.
In future, it might be desirable to implement some more sophisticated for or playlist management.
There are a few other details that I’ll cover in another post.
I am not yet sufficiently equipped to get into 4K but these days I do try to make everything Full HD whenever possible, despite Apple Computer gradually withdrawing support for all my computers as they consider them to be “vintage” models (that’s another story). When I installed the video at DINA yesterday, I forgot to take the remote control for the unbranded media player and it defaulted to 720p when I left it yesterday.
No problem, I thought, I’ll fix that in the morning. Anyway, having changed the output resolution to Full HD 1920x1080p this morning, and subsequently to 1080i when that didn’t work, it still wasn’t outputting Full HD. It looked like scaled up 720p and I think it is just one of those unavoidable pitfalls of using cheap, unbranded shit. Sometime these generic boxes are amazingly well-specced, but nothing I could think of solved the problem.
However, the Samsung UE40J5100 provided by DINA has a built-in media player, so after wasting a significant amount of time achieving nothing, I thought I would try a different approach. Sure enough, the files played back on the Samsung TV in Full HD, but all those with no audio (which is all of them) threw up an error of “Unsupported audio format” in a big dialog box with no way that I could find of disabling the warning. I could have re-rendered and re-compressed all the videos with a silent audio track, but that would take more than the five hours I had allocated to being on-site today.
But more importantly WTF? I could have clutched at a few straws and gone home to fetch the component video cable that came with the player but that I left at home, and/or getting the third media player that I have, but I had advertised being on-site 12-5pm and I can guarantee someone would turn up to see me if I stepped out of the door.
Not solving this problem took all day, and tonight the video is running at scaled-up 720p.
On the plus side, I had several visitors and several good conversations about Sheffield, roundabouts, driving, traffic, pedestrian crossings and timelapse video. Also, over dinner in the pub it provoked the first argument about pedestrian vs vehicular priority in modern cities.
Timelapse video installation showing at DINA, 32 Cambridge Street, Sheffield, UK, from 20th January to 20th February 2016. The video will be on show in the front window and viewable from the street throughout the day, but best viewed after dark.
This is part one of Phase I of a larger project called IN THE PIPE, exploring the atmospheres, experiences and aesthetics of road travel. This part is made of time-lapse video shot around Park Square Roundabout and the rest of Phase I will be shot on other junctions around the Inner Ring Road.
I will also be on-site Tuesdays and Thursdays 12-5pm for the duration of the exhibition, carrying out a mini-residency and using the time to further research, develop and document digital techniques for capturing, compiling and editing time-lapse video. Please come and say hello.
Here is a teaser trailer:
DINA (Digital Natives) is a temporary venue and art space on two floors, and is available for hire and/or exhibitions.
Music by Matt Howden aka The Mighty Sieben.
New work by Richard Bolam, made from timelapse video shot around Park Square roundabout, Sheffield, UK. It will be showing in the window of DINA, 32 Cambridge St, Sheffield (next to Henry’s), and it is best viewed from the street, after dark.
Richard Bolam will also be doing a mini-residency at DINA, continuing his research & development into digital techniques for capturing & edting timelapse video using open-source technologies.
The video will be shown from 20th January until at least February 20th (Facebook event here).
Dates & details of the residency TBC.