ITEC – Dynamic Adaptive Streaming over HTTP

VLC 2.0 “Twoflower” is now available. This official release contains basic support for DASH which means that only the basic-cm profile is supported. The newer features like dataset compatibly and buffer will be part of the next minor releases. Anyway everybody can use this features with the nightly builds or with self compiled versions from the official vlc git.

All previous patches are now officially part of VLC which will make the plugin fully compatible with the dataset out of the box. Moreover also the buffer and download thread patches as well as some minor fixes have been applied which should increase the stability of the stream.

I have rebased some old patches due to the fact that some of the patches from the “dataset patch-set” are already part of VLC. Furthermore I have added some more patches which will add a download thread and a buffer to VLC. The patch-set consists of 8 patches and is available at our download section.

The size of the buffer can be configured through the vlc preferences as shown below:

libdash is a library that simplifies DASH with the intention to make the usage of DASH streams as simple as the usage of a file. The library handles the whole HTTP connection setup, the xml parsing and the bandwidth adaptation process and with its internal buffer it tries to enable a stable stream for the user of the library. Furthermore the library supports a part of the isoffmain profile, the full basic-cm profile and HTTP byte range requests. Therefore all MPDs from our dataset are now accessible more

Everybody is invited to contribute, to get involved in and exited about DASH! A trac where you can report bugs or request new featurs or contribute is available at: Project Website

DASH in less than 5 Commands

1. Get a DASHManager Interface from the DLL (Line: 40)
2. Open the MPD (Line: 41)
3. Start the Download Process (Line: 42)
4. Read from the Stream (Line: 43)

The first patch “Patch 001: Parsing and management of the isoffmain profile” has been split into 17 patches and is now officially part of VLC and can be checked out through the git repo of vlc. The other ones are currently under review but I think they will be integrated soon.

I have seen that somebody has changed the logic in the basiccm manager. I don’t think that it is a good idea to use the best representation when no information about the client bandwidth is available.

This patch would correct this problem and use the lowest representation until enough information about the client bandwidth is available.

The patch is available here.

A new set of patches is now available which make the plugin fully compatible with the dataset from our website and a part of the actual standard. A zip package with the patches could be found here.

The profile used in the dataset is the isoffmain which is also part of the actual DASH standard that has recently been ratified as IS. Backwards compatibility with the basiccm profile is also given. The dataset could be found here. Furthermore the plugin also supports now HTTP byte range requests and the DASH mediaRange and range attributes of the init segment and the segment.

Description of the Patches:

1. Patch 001: Parsing and management of the isoffmain profile
2. Patch 002: Added byte range requests
3. Patch 003: Due to the fact that resolution switching works not smooth in VLC we have introduced two user values where the user can define his/her preferred resolution. After that the plugin will only switch between the same resolutions that fit best to this preferences:

It could be that DASH is disabled in VLC due to the fact that it is currently in an experimental state. So if you want to make sure that is enabled, you should check the “Modules.am” file in the streamfilter subdir and eventually change the line “DIST_SUBDIRS=dash” to “SUBDIRS=dash”. Sorry for that inconvenience but it is still in a beta state.

This is the presentation from the ACM Multimedia 2011. One of the most asked questions at the poster session and even at the discussion after the presentation was if we have compared our solution to the solutions that have been recently deployed by the industry i.e. Microsoft Smooth Streaming, Apple HTTP Live Streaming and Adobe Dynamic Streaming. To answer this question shortly yes we have and in anticipation of the results I can conclude that we could definitely compete with them [1], but I have to mention that we have used a more sophisticated version of this plugin that will be released in next couple of months.

[1] Christopher Müller, Stefan Lederer and Christian Timmerer, “An Evaluation of Dynamic Adaptive Streaming over HTTP in Vehicular Environments”, 4th ACM Workshop on Mobile Video, Chapel Hill, North Carolina, February 24, 2012. (to appear)

The paper “A VLC Media Player Plugin enabling Dynamic Adaptive Streaming over HTTP” will be presented at the ACM Multimedia 2011 Open Source Competition in Scottsdale. Here you can find a preview of the poster that will be presented on Tuesday. The pdf is avaialbe here.