Trying GStreamer at Windows

Since I've started working with GStreamer I had never tried it out on Windows and tonight I decided to try it out. Edward pointed me to the winbuilds and it took no more than pressing 'next' 4 or 5 times to have default applications (gst-launch, gst-inspect...) and lots of plugins. Easy enough.

That must be the reason it has been some time since I've heard complaints about installing/using GStreamer on Windows. I wonder if there are any other builds out there like these?

Thanks ylatuya!

GstCollectPads2 branch

This week I decided to grab the GstCollectPads2 patch (from bug #415754) and start a branch in my freedesktop repository for porting muxers to it. So far we've got:

• oggmux
• avimux
• matroskamux (patch by Mark)
• asfmux
• qtmux

If you always wanted GStreamer to be able to mux subtitles into your movies, now is the time to provide specs/samples/patches for it. And installing from this branch (I try to keep them up-to-date with current git master) and test it a lot in you favorite applications would help to find regressions from the porting process.

Suggestions to improve GstCollectPads2 or other use cases are also welcome.

asfmux is now at gstreamer-plugins-bad

I just pushed asfmux plugin into gstreamer-plugins-bad. So, forget the old repository, the recent code will now be at -bad.

And it now has mp3, wmv3 and wma3 support!

Live streaming of ASF content

Just pushed a couple of changes to ASF muxer plugin that enable streaming live content of ASF media. Basically it contains some fixes to timestamping and a new boolean property to asfmux called "is-live". When enabled, asfmux won't attempt to push indexes at the end of the file (as this has no sense in live streams) and also won't try to seek back to the headers to rewrite some values that it couldn't predict when started the file.

Here is the simplest example of its use in gst-launch commands:

The sender:

• gst-launch-0.10 -ve videotestsrc ! ffenc_wmv2 ! asfmux name=m is-live=true ! rtpasfpay ! udpsink host=127.0.0.1 port=3333 audiotestsrc ! ffenc_wmav2 ! m.
• gst-launch-0.10 udpsrc port=3333 ! "put the caps here" ! rtpasfdepay ! decodebin2 name=d ! queue ! ffmpegcolorspace ! autovideosink d. ! queue ! audioconvert ! autoaudiosink

Remember to replace the caps after udpsrc with the caps of the srcpad of the rtpasfpay element in the first pipeline. If you have any problems using it, please report!

The asf plugin can be found here.

ASF: we need a parser

While developing rtpasfpay I found out that I can't just do (in gst-launch syntax):

somesrc ! asfmux ! rtpasfpay ! udpsink

because the ASF headers need to be updated after the stream ends and those values are needed by rtpasfpay.

Additionally, I can't get an ASF from a file and feed it to rtpasfpay because the buffers would be unaligned with the ASF objects and packets, requiring rtpasfpay to parse the data before doing anything related to RTP. I'd say we need a parser.

The idea is to do all the parsing at the parser (obvious) and only some checks of conformance at the rtp payloader. As I had already started developing the payloader, I took it as farther as I could (without using a parser) and its current state is now at the repository. It is still unfinished (read: doesn't work).

The parser

Now I'm starting to develop the asfparse element. ASF files have 3 main parts: first there are headers, then the data (where the packets are) and lastly a series of indexes objects. The parser would, sequentially:

1. Group all the headers into a single buffer and push it
2. Push the "Data object" header (everything but the packets)
3. Put each packet into a separate buffer and push them
4. Put each of the indexes object into a separate buffer and push them
5. EOS

The parser should work both in pull or push mode, I'll start with push mode.

asfmux: index fixed, new formats

Latest asfmux changes:

• fixed simple index (seeking works)
• Support for wma version 1
• Support for wmv version 1
• Preroll time property
• Packet size property
• file id generation (instead of a previous hardcoded all zeroes)

I'd consider it ready to be called a basic asf muxer.

Feature suggestions are welcome.

ASFMux progress report

I ran some tests with asfmux yesterday and it is now capable of muxing wma2 and wmv2 nicely. Played the resulting files at totem, mplayer and media player.

The file indexes are still badly broken, so trying to seek might result in unexpected behaviours or crashing. I'm trying to fix that.

GSoC Status

GSoC's coding period started saturday and, as I've been coding a little since the accepted students announcements, I've got some results.

With a lot of help from Mike, that is also working with ASF, asfmux currently is capable of muxing WMAv2 and WMVv2, which means that most of the base code of the muxer is ready. It still lacks the indexes, but that's what I'm working on these days.

Unfortunately, I still won't be working full speed at GSoC 'till the end of next week, when I'll be on university vacation.

If you'd like to take a look at the code, my repository is here.

ASF Inspect Tool

So, if you are learning/working on ASF media, Microsoft has this tool[1] for Windows (it's free) that might help you, I just found it and haven't really tested it, just explored some files and it is much better than opening them in ghex.

[1] http://www.microsoft.com/windows/windowsmedia/forpros/format/asfviewer.aspx

GSoC '09 Start up

Finally got some time to post here about me getting accepted into GSoC this year! Yay!!!

The project

Basically, develop ASFMux and RTPASFPay (or something more readable than this). ASFMux will be featureful, supporting stream prioritization, stream mutual exclusion and timed scritpting. David Schleef will be my mentor this year.

The GIT Repository (http://cgit.freedesktop.org/~thiagoss/)

I'll be hosting my code in my personal freedesktop git repositories. Initially I thought on using a branch out of -plugins-bad, but then I thought that it would be better to have a single plugin tree, because people can build and install without destroying their -plugins-bad install.

Current stage

So far I got a basic muxer stub and started working on sending the header bytes. The code at git has a trunk base folder, but that's because I started working with svn and them migrated to git, I'll remove that in my next push.

I just wanted to make the project start public. I'll be updating the status of it here regularly.

Now I need to get some sleep, it's getting late here. Good night!

GSoC '09 UFCG Status

UFCG (Universidade Federal de Campina Grande) is the university I study at, and last year it seems that I was the only one that applied to GSoC. 

This year, I decided to spread the word about it and motivate people to participate. When the program was announced I kept sending information and tips on the students mailing lists and giving short presentations about the program. Happily, we got 5 students accepted this year! Much better than only 1 last year. They are (name - project - course):

• André Dieb Martins - Enlightenment - Electrical Engineering
• Danilo Araújo de Freitas - Python - Computer Science
• Felipe Ribeiro Nogueira Barbosa - PHP - Computer Science
• Thiago de Freitas Oliveira Araújo - NuiGroup - Electrical Engineering
• Thiago Sousa Santos (me) - GStreamer - Computer Science

Congrats you all and to all other accepted students. Time to work hard and complete your projects!

Telepathy tutorial

That was the search I tried at google while I started to study telepathy, but it was amazing and funny the amount of tutorials I found on telepathy (the psychic stuff). I didn't try them, if someone feels up to it, please tell me how did it go :-P

After reading telepathy wiki, I went to #telepathy and davyd pointed me to the book they're writing, and so far it was the better source of information about it. If you are willing to learn about telepathy, try it out and give them feedback.

New feature on gst-launch

Now you can add the flag --eos-on-shutdown (or simply -e), meaning that you want it to send EOS to the pipeline even when you stop it by sending a sigint (ctrl + c). This way, the EOS will travel through the elements, and they can finish properly their work. This is important for muxers.

When -e is enabled, if you press ctrl+c and it hangs while waiting for the EOS, just press again and the default behaviour will be executed (shut down the pipeline immediately and quit).

A example use case for the feature: to receive and mux live streams using gst-launch.

For the devels: the commit - the bug

Happy new year!

This year had a slow start, but it seems that things are heating up.

1) I decided to be back on bikes (after 5 years), going twice a week for about 30km, starting at 5 AM. Surprisingly, I'm riding with the same group I used to and they remember me (I was 15 by that time!). Note: I need a new bike.

2) Google's Summer of Code is starting again this year and I'll try to participate again for GStreamer. From the tasklist, ASF muxing support and mpeg2ts interested me the most. But I'm open to suggestions.

Also, I've been asked to do a small presentation at the university to the Computer Science department (students and teachers) next wednesday. And I've already started reading ASF spec.

3) University classes are back (1 year to finish it!)

4) As my undergraduation is almost over, the amount of requests for small parallel projects has increased, which is good, most of them are simple web-based CRUD applications. They take little time and are a good source of money for a student.

Finally it is starting! Happy new year, everyone!