Petter Reinholdtsen

The layered video playout server created by Sveriges Television, CasparCG Server, entered Debian today. This completes many months of work to get the source ready to go into Debian. The first upload to the Debian NEW queue happened a month ago, but the work upstream to prepare it for Debian started more than two and a half month ago. So far the casparcg-server package is only available for amd64, but I hope this can be improved. The package is in contrib because it depend on the non-free fdk-aac library. The Debian package lack support for streaming web pages because Debian is missing CEF, Chromium Embedded Framework. CEF is wanted by several packages in Debian. But because the Chromium source is not available as a build dependency, it is not yet possible to upload CEF to Debian. I hope this will change in the future.

The reason I got involved is that the Norwegian open channel Frikanalen is starting to use CasparCG for our HD playout, and I would like to have all the free software tools we use to run the TV channel available as packages from the Debian project. The last remaining piece in the puzzle is Open Broadcast Encoder, but it depend on quite a lot of patched libraries which would have to be included in Debian first.

A fun way to learn how to program Python is to follow the instructions in the book "Learn to program with Minecraft", which introduces programming in Python to people who like to play with Minecraft. The book uses a Python library to talk to a TCP/IP socket with an API accepting build instructions and providing information about the current players in a Minecraft world. The TCP/IP API was first created for the Minecraft implementation for Raspberry Pi, and has since been ported to some server versions of Minecraft. The book contain recipes for those using Windows, MacOSX and Raspian. But a little known fact is that you can follow the same recipes using the free software construction game Minetest.

There is a Minetest module implementing the same API, making it possible to use the Python programs coded to talk to Minecraft with Minetest too. I uploaded this module to Debian two weeks ago, and as soon as it clears the FTP masters NEW queue, learning to program Python with Minetest on Debian will be a simple 'apt install' away. The Debian package is maintained as part of the Debian Games team, and the packaging rules are currently located under 'unfinished' on Salsa.

You will most likely need to install several of the Minetest modules in Debian for the examples included with the library to work well, as there are several blocks used by the example scripts that are provided via modules in Minetest. Without the required blocks, a simple stone block is used instead. My initial testing with a analog clock did not get gold arms as instructed in the python library, but instead used stone arms.

I tried to find a way to add the API to the desktop version of Minecraft, but were unable to find any working recipes. The recipes I found are only working with a standalone Minecraft server setup. Are there any options to use with the normal desktop version?

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A few hours ago, a new and improved version (2.4) of the VLC bittorrent plugin was uploaded to Debian. This new version include a complete rewrite of the bittorrent related code, which seem to make the plugin non-blocking. This mean you can actually exit VLC even when the plugin seem to be unable to get the bittorrent streaming started. The new version also include support for filtering playlist by file extension using command line options, if you want to avoid processing audio, video or images. The package is currently in Debian unstable, but should be available in Debian testing in two days. To test it, simply install it like this:

apt install vlc-plugin-bittorrent

After it is installed, you can try to use it to play a file downloaded live via bittorrent like this:

vlc https://archive.org/download/Glass_201703/Glass_201703_archive.torrent

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FNs menneskerettighetserklæring artikkel 13 første punkt lyder som følger:

Enhver har rett til å bevege seg fritt og til fritt å velge oppholdssted innenfor en stats grenser.

Det er altså en menneskerett å kunne bevege seg fritt i landet. For å bevege seg fritt i landet, så må en kunne bevege seg uten å bli sporet. Det vil i dagens samfunn innebære å bevege seg uten å legge igjen digitale spor og uten å være radiomerket. Hvis en vet at ens bevegelser, hvor en befinner seg når, og hvem som befinner seg i nærheten, blir samlet inn og gjort tilgjengelig for fremmede, det være seg myndighetene eller private organisasjoner, så kan en ikke lenger bevege seg fritt. Dette gjør at det er en forutsetning for å ha glede av retten til å bevege seg fritt i landet at en motstår fristelsen til å legge igjen digitale spor når en betaler for seg. Rettigheter som ikke blir brukt, blir fjernet. Den eneste måten i dag å unngå å legge igjen digitale spor når en betaler for seg, er å betale med kontanter, samt takke nei til å legge igjen navn og adresse (slik f.eks. Elkjøp ber om — jeg sier de kan legge inn «anonym anonym» når datasystemet deres trenger et navn). Personlig anbefaler jeg å konsekvent bruke kontant betaling når man beveger seg rundt, for å bidra til forsvaret av menneskerettighetene i Norge. Kanskje noe også for deg? Merk at det ikke er tilstrekkelig for å unngå sporing å betale med kontanter, men det er et lite steg i riktig retning.

Det er flere andre argumenter i tillegg til menneskerettighetsargumentet for å bruke kontanter. I går hadde Dagbladet en utmerket kommentar av sin journalist John Olav Egeland om hvilket kontantløst diktatur som venter oss hvis mange nok slutter å insistere på å betale med kontanter. Jeg anbefaler deg å lese den.

Som vanlig, hvis du bruker Bitcoin og ønsker å vise din støtte til det jeg driver med, setter jeg pris på om du sender Bitcoin-donasjoner til min adresse 15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b. Merk, betaling med bitcoin er ikke anonymt. :)

Yesterday, I had the pleasure of watching on Frikanalen the OWASP talk by Scott Helme titled "What We’ve Learned From Billions of Security Reports". I had not heard of the Content Security Policy standard nor its ability to "call home" when a browser detect a policy breach (I do not follow web page design development much these days), and found the talk very illuminating.

The mechanism allow a web site owner to use HTTP headers to tell visitors web browser which sources (internal and external) are allowed to be used on the web site. Thus it become possible to enforce a "only local content" policy despite web designers urge to fetch programs from random sites on the Internet, like the one enabling the attack reported by Scott Helme earlier this year.

Using CSP seem like an obvious thing for a site admin to implement to take some control over the information leak that occur when external sources are used to render web pages, it is a mystery more sites are not using CSP? It is being standardized under W3C these days, and is supposed by most web browsers

I managed to find a Django middleware for implementing CSP and was happy to discover it was already in Debian. I plan to use it to add CSP support to the Frikanalen web site soon.

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If you read my blog regularly, you probably know I am involved in running and developing the Norwegian TV channel Frikanalen. It is an open channel, allowing everyone in Norway to publish videos on a TV channel with national coverage. You can think of it as Youtube for national television. In addition to distribution on RiksTV and Uninett, Frikanalen is also available as a Kodi addon. The last few days I have updated the code to add more features. A new and improved version 0.0.3 Frikanalen addon was just made available via the Kodi repositories. This new version include a option to browse videos by category, as well as free text search in the video archive. It will now also show the video duration in the video lists, which were missing earlier. A new and experimental link to the HD video stream currently being worked on is provided, for those that want to see what the CasparCG output look like. The alternative is the SD video stream, generated using MLT. CasparCG is controlled by our mltplayout server which instead of talking to mlt is giving PLAY instructions to the CasparCG server when it is time to start a new program.

By now, you are probably wondering what kind of content is being played on the channel. These days, it is filled with technical presentations like those from NUUG, Debconf, Makercon, and TED, but there are also some periods with EMPT TV and P7.

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As part of my involvement in the Nikita archive API project, I've been importing a fairly large lump of emails into a test instance of the archive to see how well this would go. I picked a subset of my notmuch email database, all public emails sent to me via @lists.debian.org, giving me a set of around 216 000 emails to import. In the process, I had a look at the various attachments included in these emails, to figure out what to do with attachments, and noticed that one of the most common attachment formats do not have an official MIME type registered with IANA/IETF. The output from diff, ie the input for patch, is on the top 10 list of formats included in these emails. At the moment people seem to use either text/x-patch or text/x-diff, but neither is officially registered. It would be better if one official MIME type were registered and used everywhere.

To try to get one official MIME type for these files, I've brought up the topic on the media-types mailing list. If you are interested in discussion which MIME type to use as the official for patch files, or involved in making software using a MIME type for patches, perhaps you would like to join the discussion?

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My current home stereo is a patchwork of various pieces I got on flee markeds over the years. It is amazing what kind of equipment show up there. I've been wondering for a while if it was possible to measure how well this equipment is working together, and decided to see how far I could get using free software. After trawling the web I came across an article from DIY Audio and Video on Speaker Testing and Analysis describing how to test speakers, and it listing several software options, among them AUDio MEasurement System (AUDMES). It is the only free software system I could find focusing on measuring speakers and audio frequency response. In the process I also found an interesting article from NOVO on Understanding Speaker Specifications and Frequency Response and an article from ecoustics on Understanding Speaker Frequency Response, with a lot of information on what to look for and how to interpret the graphs. Armed with this knowledge, I set out to measure the state of my speakers.

The first hurdle was that AUDMES hadn't seen a commit for 10 years and did not build with current compilers and libraries. I got in touch with its author, who no longer was spending time on the program but gave me write access to the subversion repository on Sourceforge. The end result is that now the code build on Linux and is capable of saving and loading the collected frequency response data in CSV format. The application is quite nice and flexible, and I was able to select the input and output audio interfaces independently. This made it possible to use a USB mixer as the input source, while sending output via my laptop headphone connection. I lacked the hardware and cabling to figure out a different way to get independent cabling to speakers and microphone.

Using this setup I could see how a large range of high frequencies apparently were not making it out of my speakers. The picture show the frequency response measurement of one of the speakers. Note the frequency lines seem to be slightly misaligned, compared to the CSV output from the program. I can not hear several of these are high frequencies, according to measurement from Free Hearing Test Software, an freeware system to measure your hearing (still looking for a free software alternative), so I do not know if they are coming out out the speakers. I thus do not quite know how to figure out if the missing frequencies is a problem with the microphone, the amplifier or the speakers, but I managed to rule out the audio card in my PC by measuring my Bose noise canceling headset using its own microphone. This setup was able to see the high frequency tones, so the problem with my stereo had to be in the amplifier or speakers.

Anyway, to try to role out one factor I ended up picking up a new set of speakers at a flee marked, and these work a lot better than the old speakers, so I guess the microphone and amplifier is OK. If you need to measure your own speakers, check out AUDMES. If more people get involved, perhaps the project could become good enough to include in Debian? And if you know of some other free software to measure speakers and amplifier performance, please let me know. I am aware of the freeware option REW, but I want something that can be developed also when the vendor looses interest.

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Bittorrent is as far as I know, currently the most efficient way to distribute content on the Internet. It is used all by all sorts of content providers, from national TV stations like NRK, Linux distributors like Debian and Ubuntu, and of course the Internet archive.

Almost a month ago a new package adding Bittorrent support to VLC became available in Debian testing and unstable. To test it, simply install it like this:

apt install vlc-plugin-bittorrent

Since the plugin was made available for the first time in Debian, several improvements have been made to it. In version 2.2-4, now available in both testing and unstable, a desktop file is provided to teach browsers to start VLC when the user click on torrent files or magnet links. The last part is thanks to me finally understanding what the strange x-scheme-handler style MIME types in desktop files are used for. By adding x-scheme-handler/magnet to the MimeType entry in the desktop file, at least the browsers Firefox and Chromium will suggest to start VLC when selecting a magnet URI on a web page. The end result is that now, with the plugin installed in Buster and Sid, one can visit any Internet Archive page with movies using a web browser and click on the torrent link to start streaming the movie.

Note, there is still some misfeatures in the plugin. One is the fact that it will hang and block VLC from exiting until the torrent streaming starts. Another is the fact that it will pick and play a random file in a multi file torrent. This is not always the video file you want. Combined with the first it can be a bit hard to get the video streaming going. But when it work, it seem to do a good job.

For the Debian packaging, I would love to find a good way to test if the plugin work with VLC using autopkgtest. I tried, but do not know enough of the inner workings of VLC to get it working. For now the autopkgtest script is only checking if the .so file was successfully loaded by VLC. If you have any suggestions, please submit a patch to the Debian bug tracking system.

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This morning, the new release of the Nikita Noark 5 core project was announced on the project mailing list. The free software solution is an implementation of the Norwegian archive standard Noark 5 used by government offices in Norway. These were the changes in version 0.2 since version 0.1.1 (from NEWS.md):

• Fix typos in REL names
• Tidy up error message reporting
• Fix issue where we used Integer.valueOf(), not Integer.getInteger()
• Change some String handling to StringBuffer
• Fix error reporting
• Code tidy-up
• Fix issue using static non-synchronized SimpleDateFormat to avoid race conditions
• Fix problem where deserialisers were treating integers as strings
• Update methods to make them null-safe
• Fix many issues reported by coverity
• Improve equals(), compareTo() and hash() in domain model
• Improvements to the domain model for metadata classes
• Fix CORS issues when downloading document
• Implementation of case-handling with registryEntry and document upload
• Better support in Javascript for OPTIONS
• Adding concept description of mail integration
• Improve setting of default values for GET on ny-journalpost
• Better handling of required values during deserialisation
• Changed tilknyttetDato (M620) from date to dateTime
• Corrected some opprettetDato (M600) (de)serialisation errors.
• Improve parse error reporting.
• Started on OData search and filtering.
• Added Contributor Covenant Code of Conduct to project.
• Moved repository and project from Github to Gitlab.
• Restructured repository, moved code into src/ and web/.
• Updated code to use Spring Boot version 2.
• Added support for OAuth2 authentication.
• Fixed several bugs discovered by Coverity.
• Corrected handling of date/datetime fields.
• Improved error reporting when rejecting during deserializatoin.
• Adjusted default values provided for ny-arkivdel, ny-mappe, ny-saksmappe, ny-journalpost and ny-dokumentbeskrivelse.
• Several fixes for korrespondansepart*.
• Updated web GUI:
  • Now handle both file upload and download.
  • Uses new OAuth2 authentication for login.
  • Forms now fetches default values from API using GET.
  • Added RFC 822 (email), TIFF and JPEG to list of possible file formats.

The changes and improvements are extensive. Running diffstat on the changes between git tab 0.1.1 and 0.2 show 1098 files changed, 108666 insertions(+), 54066 deletions(-).

If free and open standardized archiving API sound interesting to you, please contact us on IRC (#nikita on irc.freenode.net) or email (nikita-noark mailing list).

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