Base-Art / Misc

GStreamer and on-disk videos buffering

Philippe Normand — 2010-01-22T09:51:42.000004+02:00

A really nice feature every video player using GStreamer and playbin2 should have is media on-disk buffering. Even though it is supported only for Quicktime and Flash videos currently it remains one good improvement of the user experience if you are an avid consumer of Apple trailers and flv :)

Under the hood the magic is in queue2 and uridecodebin but you mostly interface with playbin2. Here is the action plan:

Add the "download" flag to the playbin2 flags property
Upon reception of GST_MESSAGE_BUFFERING messages on the bus, add an idle source to the main loop (for instance)
In that source create a gst_query_new_buffering() query with GST_PERCENT_FORMAT format perform the query to playbin2
Use gst_query_parse_buffering_range() to get the stop value and compute the fill_status value
Notify your UI of the fill level

Additionally you can allow the user to save the buffered media for later off-line consumption :) The media is buffered by queue2 in the tmp folder, the exact file location, temp-location queue2 property, can be retrieved by connecting to the "deep-notify::temp-location" signal of playbin2. You also need to make sure that the temporary file is removed when the user exits from your application, GStreamer doesn't automatically take care of that, as far as I could see.

This is what Totem does, as far as I could understand its code. This is also how I implemented (yet to merge) it in WebKitGTK+:

And to provide a simple example I added this feature to the gst-python play.py example, available in a gist after the break!

Python, sockets, GStreamer and the Garbage collector

Philippe Normand — 2009-05-23T22:56:20.000005+02:00

Long time no blog, eh? Anyway I was today hooking up Telepathy Stream Tubes with GStreamer so that I could stream video over local-xmpp, go figure why... :)

Everything was fine:

on one side, offer a stream tube in a multi-user room and setup a pipeline like this one:
```
videotestsrc ! gdppay ! multifdsink
```
on client side, join the room and accept the tube, hooked into the following pipeline with a socket:
```
fdsrc ! gdpdepay ! xvimagesink
```
when server is notified of new client, add its socket fd in multifdsink and start playback

But it wasn't working, multifdsink was removing the fd by itself from the list and client wasn't receiving data. I spent some time this afternoon trying to figure out why and thought I might share the solution, if it can serve to anyone using multifdsink in Python. Because I wasn't keeping references of the client socket instances in my code, they were garbage-collected by Python, so the fd was becoming invalid, hence the rejection by multifdsink.

Keeping a list of the socket instances and cleaning it up when the sink emits the client-removed signal does the trick and I got my video streaming over local-xmpp working. Those Tubes are so much fun, thanks Collabora & Telepathy folks for this nice stuff!

Hi Planet GNOME!

Philippe Normand — 2008-02-27T22:49:37.000002+02:00

Just a quick post to say hi to the GNOME community. Thanks Jeff for adding me!

So I'm Philippe (philn on IRC), working for Fluendo on the Elisa MediaCenter, writing Python fluently during work hours for fun and profit and off work, only for fun :)

I regularly write news about Elisa, did some posts about Pigment and GStreamer too and a good bunch of posts related to various hacks and ramblings about Python.

So expect new posts about Pigment and Elisa towards better integration in the GNOME desktop. I'll also try to blog about my little growing experience in the GStreamer world :)

N810: first impressions

Philippe Normand — 2008-02-12T22:17:45.000001+02:00

Two weeks ago I bought my N810 with the discount code kindly offered by Nokia for the Maemo development program. The device is really nice, the OS2008 provides a totally new user experience (compared to the version I used on my N770). So here are few remarks I have after few weeks of usage:

the padlock slider is too easy to activate.
the keyboard is coool but I sometimes have difficulties with the keys of the first row in the keyboard. To me they are slightly too near from the screen.
I dislike the kinda "micro" USB plug, it looks like some Nokia specific plug, a mini-usb plug would have been more handy so that I could use the same USB wire as for my camera.

So far I used the IM a bit with Frank for a video chat and with Mom for an audio-only GoogleTalk chat. Sound is good but video quality was bad, I need to make more tests I guess :)

Played a bit with MediaStreamer and Coherence, everything works fine, excepted seeking that's lacking because Coherence HTTP server doesn't yet support HTTP range requests.

I also did some media transcoding so that I can watch videos on the device. Videos need to be encoded in MP4 at some specific resolutions. Fortunately there's an handy script at maemo.org to do the whole job for me :)

Last weekend I gave a try to geottagging using the documentation on Maemo wiki. I ended up with a nice KML file that can be displayed on Google Earth and Google Maps (see below too). I'll directly integrate these features in my gallery soon, geotagging is an interesting thing, especially for my next holidays... :)

Agrandir le plan

In the coming weeks I'll start developing user-interfaces using the Python EFL libraries. I'll most likely play a bit with the Coherence MediaRenderer called Compere, so far implemented using PyGame and try to rework it with the EFL libs... More to come later :)

edit: Frank the Coherence guru reminds me that Coherence de facto supports HTTP range requests but MediaStreamer HTTP client doesn't implement the seek requests correctly... :)

Back from FOSDEM

Philippe Normand — 2007-02-26T11:00:41+02:00

So I was at FOSDEM 2007. Nice conf, many people and interesting talks. I crashed at Thomas'_ place for the week-end, thanks dude :-) Of particular interest:

OLPC : laptops for children
OpenMoko : open-source phone
Metisse : not a 3D desktop!

I wish I could attend to OneTeam and Telepathy talks. Thomas told me about a nice project presented there as well: MetaSploit.

Elisa talk went quite well, I got many interesting questions especially about the PVR we plan to bring in at some point. The Seamless guy showed up at the end of the talk, Seamless is a DVD player written in Python and using GStreamer. It wasn't updated for a while, still using gst 0.8 as I understood. But soon it'll be ported to 0.10 and maybe at some point an Elisa DVD plugin will be available :)

Stefan gave me a N770 so that I can hack on a Elisa client for Maemo platform, thanks again Stefan!

New home, new country, same job

Philippe Normand — 2006-09-01T20:51:39.000004+02:00

After nearly 6 months spent living in Lyon, I headed south once more, to Barcelona :) I entered a new flat with 2 other frenchie fellows, we'll be damn fine there!!

We still have some administrative paper work to do, but it can wait, we did the essential ones.. The flat is a bit messy right now, there are stuff to unpack lying around, and pieces to put back together, but it will get better soon ;)

It seems there are many things to visit right there. Beach is nice too, and mountains are not that far... So much to discover!

So, I will be in the same office as my co-workers at Fluendo, still working on Elisa. I think the project will evolve faster and better in this new context. Talking with people face to face is really better than IRC or video-conferencing; and by the way Fluendo folks are so fun to work with :)

Switching server

Philippe Normand — 2006-08-03T14:56:53.000003+02:00

This evening base-art.net, pythonfr.org and few other hosted domains should be un-available while we migrate websites to a brand new dedicated server. So, fellow readers, don't be surprised ;-)

Things will come back up this night hopefully. I'm still reachable by mail, phil at base-art dot net. Jkx, the summer-server-migrator, did a good job and won few beers :-)

Pimp this rage

Philippe Normand — 2006-04-21T00:28:33.000004+02:00

Looks like Raster has been hacking on a media center thingy. So far it looks great, i've watched the demo video, installed rage in no time and got it running in, well, even less time :) I must say i'm really impressed by the look and feel of the app. Need to keep an eye on this !

I've even seen a -gstreamer option, but somehow didn't worked out. Also video thumbnail build/playback didn't worked, but i'm not really up-to-date with my EFLs these days, and Raster warned Rage could make your computer blow out :) Anyway, keep up good work Raster!

Watch out the demo video, it's really impressing.

So (privately) delicious

Philippe Normand — 2006-03-19T12:39:28.000006+02:00

Del.icio.us folks added the so awaited private bookmarks saving support. That's a great step for this service, i need it to save links to private websites or htaccess protected websites or even job-related locations.

By default the new option is not activated, and once active you need to validate a little checkbox on the "new-post" page to keep the link private.

New home, new job

Philippe Normand — 2006-03-17T19:31:23.000004+02:00

Last month i moved from Brest to Lyon, for a new job. I'm now working with Fluendo folks on a Gstreamer/Python media center open-source project since March 1st.

The project is very ambitious, the plan is to provide a cross-platform, great looking media-center supported by a community of developers and users (like Gstreamer for instance). We are working hard, i'll probably post more on that topic later on.

So, moving on was a bit hard, including flat-hunting, lots of administrative tasks (phone, electricity, dsl subscriptions and i forget some others). I'm not finished yet, but quite lazy for the remaining ones. Flat hunting was hard but my new home is quite good, i'm happy with it ;) And many thanks to Gagoune for hosting me during few weeks!

BTW hello to planet gstreamer! Very happy to be here :)