Earlier releases of the Zonbu OS had issues with the playback of MPEG2 files as I noted here on August 4th.
With the latest software release, 5.803, this issue appears to be resolved.
MPEG2 files now appear to be playing with full hardware acceleration.
What this means is that the complex decoding of the MPEG2 stream is offloaded from the main processor, to a dedicated MPEG2 decoding subsystem. This is important as decoding video is an intense task and the Zonbu has a relatively modest processor…
Load Observations for MPEG2
Playback of any of a cross section of local or web based MPEG2 files (like those generated by MythTV systems with PVR-150/250/350/500 encoder cards) results in CPU load varying between 20% and 35%, after an initial spike to almost 100% as the movie player launches.
At a 20% processor load, you can easily play back MPEG2 video in a window and multi-task at the same time.
However, this utility value is falling for most people as MPEG2 video, while the standard in the digital television world (for Digital Cable TV), is becoming less and less common on the Internet due to its large file size. That being said, there is still a huge amount of MPEG2 content already on the ‘Net.
The MPEG Roadmap
MPEG4 (the standard for Digital TV over DSL) and Windows WMV format are emerging as the video formats of choice on the Internet due to their efficiency. An identical standard definition video stream that is ~4Mbps on MPEG2 could be reproduced with ~1.5Mbps or less utilizing MPEG4 encoding.
The recent announcement that Flash 9 now supports MPEG4 will likely mean a significant uptick in the amount of MPEG4 content on the Internet over the coming year(s).
According to the Via website, the CX700 chipset utilized in the Zonbu hardware has:
Flawless Digital Media Playback
VIA UniChrome Pro includes native support for the most popular digital video and audio formats through hardware MPEG-2 playback and acclaimed VIA Vinyl HD Audio suite, supporting up to eight high definition channels delivering a richer all-around digital media experience.
Further, the DMP Electronics site for the eBox 4854, which appears to be the hardare platform for the Zonbu, claims that the unit supports accelerated MPEG4/WMV9 decoding acceleration. Strangely, it does not mention MPEG2 acceleration, but I believe this is an oversight.
Integrated VIA UniChrome 2D/3D Graphics with MPEG4/WMV9 decoding accelerator
It is unclear if this is supported under the Linux driver yet, so perhaps someone from Zonbu can shed further light on the topic.
MPEG4 Encoding and Playback
In the course of my work I’ve been doing a lot of research and some development around the multi-cast transport of digital video. As a result I’ve been playing with a lot of MPEG2 and MPEG4 streams, as well as the related encoding hardware and network transport layers.
At the home user end of the spectrum, one device that I’ve been playing with is the open source Neuros OSD.
This tiny, <$250 device is meant to plug in to your TV/DVD player and can encode various video inputs directly to the MPEG4 format, suitable for playback on mobile devices like the iPod, or various portable media players.
It has a CF Slot, an SD slot, and an ethernet jack. It also has a USB 2.0 port that you can hook an external hard drive too.
I used it to capture a 5 minute clip from the latest James Bond DVD at 640 X 480 at a bit rate of approximately 2.5 Mbps, the highest capture quality it provides. (Using it for small screen portable devices you would usually encode at half or less than that resolution/bitrate).
Playing the MPEG4 Bond clip back on the Zonbu resulted in a CPU load of 35-50%. There was a high level of variation in the load, especially during high action scenes, as MPEG4 is more complex than MPEG2 video. Even during extremely high action chase scenes the load didn’t go materially over 50% and even then it was momentary.
MPEG2 playback is excellent, again showcasing the Zonbu as an impressive “out-of-the-box” multi-media web terminal. Wow, that’s a mouthful.
To have the same experience on a Windows desktop you would need to install a big cross-section of plug-ins and codecs. The Zonbu has them all from day one making it attractive for non-tech savvy users who just want things to work when they click on them.
MPEG4 playback appears that it may be accelerated in the current release, although I would like this confirmed by Zonbu staff. The quality of the playback was great. I have not been able to recreate the “stuttering” that I saw once before and mentioned in a previous post.
I should also mention that I had Firefox running with 4-6 tabs open during this testing, although it was idle while the playback was occuring.
Not only have Zonbu corrected the earlier MPEG2 bug but the device continues to shine as a multi-media playback device.