Disclaimer: This analysis is merely an objective analysis of the coding features the encoder uses and not an analysis of the subjective or objective picture quality of the encoder. It’s also worth saying that this information is from a small clip but in the main short clips can provide a good indication of the coding decisions an encoder is making.
Early stage encoders like the one used in the BBC World Cup UHD trial are interesting in that they provide an insight into the development process of a encoder and what coding tools encoder manufacturers have decided to use first (often with limited processing power). This information usually remains under NDA but public use of the encoder means anyone can perform analysis on it.
A very good introduction to HEVC coding tools can be found here: http://forum.doom9.org/showthread.php?t=167081
Thanks to the help provided by Parabola Research in producing this post. You can download a bitstream analysis report from Parabola Explorer Pro 3.0 below. This report helped produce the analysis below.
In no particular order:
All in all, not really a surprise. At this early stage it's no real surprise that people like Netflix are saying “We're not seeing efficiency gains being claimed by HEVC encoding vendors"1 and such a limited use of the toolkit is the main reason why
The report from Parabola Explorer Pro can be found here: http://downloads.obe.tv/Parabola-Explorer-Pro-analysis-of-Rio-Stream.pdf
As announced the BBC have launched a UHD1 channel using HEVC on the COM8 multiplex. This uses standard DVB-T2 modulation parameters and can be captured using an off the shelf USB capture stick. FFmpeg supports HEVC decoding and by extension most other Open Source multimedia software. So the output of ffprobe looks like this:
Input #0, mpegts, from 'BBCUHD1.ts': Duration: 00:00:45.35, start: 404.054433, bitrate: 35862 kb/s Program 61440 Metadata: service_name : Test service_provider: Stream #0:0[0x65]: Video: hevc (Main) ( / 0x0024), yuv420p(tv), 3840x2160 [SAR 1:1 DAR 16:9], 59.94 fps, 59.94 tbr, 90k tbn, 59.94 tbc Stream #0:1[0x66](eng): Audio: aac_latm ( / 0x0011), 48000 Hz, stereo, fltp Program 61504 Metadata: service_name : Test. service_provider: Stream #0:0[0x65]: Video: hevc (Main) ( / 0x0024), yuv420p(tv), 3840x2160 [SAR 1:1 DAR 16:9], 59.94 fps, 59.94 tbr, 90k tbn, 59.94 tbc Stream #0:1[0x66](eng): Audio: aac_latm ( / 0x0011), 48000 Hz, stereo, fltp
As expected Main Profile HEVC at 59.94 fps is used. Let's try decoding it (Sandy Bridge Xeon 4-cores 3.4GHz):
./ffmpeg -benchmark -i BBCUHD1.ts -f rawvideo -y /dev/null
frame= 187 fps= 45 q=0.0 size= 2272050kB time=00:00:03.11 bitrate=5966002.6kbit
45fps is not bad but significantly below 59.94fps to watch the match in realtime. On the OpenHEVC decoder that will eventually have parts merged in FFmpeg on a 2x 6 core Xeon, it's possible to decode at around 127fps. This is because it has intrinsics for more functions (notably the transforms) than mainline FFmpeg. However, FFmpeg does not accept intrinsics for maintenance and performance reasons. Plans are afoot to get this viewable in realtime before the first match is on. More technical information will be posted in due course.
At the moment the feed is showing a recording of some trees and the back of the W12 Media Village: http://www.obe.tv/images/UHD.png
Read part two which has an analysis of the HEVC encoding technology here: http://obe.tv/about-us/obe-blog/item/13-a-look-at-the-hevc-encoder-bbc-uhd-world-cup-part-2
We'll be having another meetup at FOSDEM this weekend at 2pm in the BoF room. Please check signage in building H to confirm this.
After a huge amount of work and testing OBE Realtime 1.0 has been released today. This release is in use worldwide for a variety of different contribution and distribution services. It's worth pointing out this release is designed for general purpose use - this is to aid people testing OBE out on hardware that they already have as opposed to the recommended hardware. Therefore this release won't maximise CPU and quality on the most recent hardware. Currently the D100 is in QA and when the product ships code optimising for the most recent hardware will be released.
We will be having our annual IBC Open Source meetup on Saturday 14th, at the UK Hospitality Area 4.A61a in Hall 4 starting from 1800. Drink and snacks will be provided. There is no need to RSVP and feel free to pass this message on. (Note this is a different venue to last year)
IBC 2013 (4.A61g) – Icelandic Broadcasters have deployed Open Broadcast Encoder (OBE), a professional DVB encoder, usable on commodity hardware and open source, in a variety of contribution and distribution roles.
IBC 2013 (4.A61g) – Audio Visual Global J.S.C (AVG) which owns An Vien Television has selected Open Broadcast Encoder (OBE) to upgrade their DTH and DTT services. AVG uses OBE to encode its MPEG-4/AVC Direct to Home (DTH) satellite and Digital Terrestrial Television (DTT) services as well as for head-end contribution encoding.
AVG Television’s deployment of OBE is one of the largest deployments of software DVB encoders for DTH and DTT encoding. OBE gives AVG a cost-effective platform with unrivalled flexibility and stability whilst at the same time future-proof. AVG were also able to customise OBE to meet market-specific needs, something not possible with proprietary competitors. OBE allowed AVG to increase its channel portfolio, allowing greater choice for customers.