Recently in Codecs Category

Updates on WebM Support - All Aboard!

By
phillc
on June 2, 2010 2:36 PM | | Comments (0) | TrackBacks (0)
As could probably be predicted, there's been a lot more press around WebM over the last ten days or so. A few articles are worth noting.

CNET posted a reasonably ordinary piece regarding the quality of WebM, when compared against H.264. However, there were two interesting links in this piece. 

The first pointed to a WebM project page where the indepth encoding parameters for WebM content are outlined. If you're planning to create WebM files, reading this page is essential. 

The second link, to the quAVlive website provides some various examples of H.264 (using x264) encoding compared against WebM. I can't really see a lot of visual difference in the "Sunflower" example. However, it is easily clear to my eyes, without even enlarging the screenshots, that in "Park Joy" and "Riverbed" H.264 is certainly superior. I would like to have seen more information regarding the time taken to transcode these examples, with each codec, and the resulting file sizes. Picture quality isn't always everything, transcode time and storage requirements should also be taken into consideration.

Everyone's jumping on the WebM bandwagon with software and hardware support. Gstreamer claims full plugin support, which means in turn there is Moovida support and the Transmaggedon transcoder can also output VP8 codec files, although not in the Matroska/WebM container yet. Not to be outdone, Flumotion, will also stream live VP8/WebM content. The Miro Video Converter will also output valid VP8/WebM files, claiming to be the first to do so. The list could go on, but the easiest thing is to probably just keep tabs on the WebM project page listing all the supported devices and software tools, both commercial and open source.

Also worth a shout is the fact that both Mozilla and Opera are pushing for VP8/WebM to be specifically included in the HTML5 specification. Previously, major browser makers couldn't agree on one specific video file format - Mozilla and Opera backing Ogg Theora and Apple sticking with H.264. I can't see that particular situation changing now. 

WebM - The New Open Source Codec on the Block

By
phillc
on May 27, 2010 3:59 PM | | Comments (0) | TrackBacks (0)
In August 2009, Google acquired codec developer On2 Technologies for a rumoured $106 million. The flagship On2 codec was VP8 and it was also rumoured at the time that Google may open source this technology in the future, although a number of challenges lay ahead.

Late last week this rumour became reality and WebM was born. Alongside Theora and Dirac, WebM now enters the open source HTML 5 ready codec battle. Almost immediately all major web browsers, except one, but including Internet Explorer announced support for the codec. Using the might and muscle of Google WebM must have a solid chance of taking on the dominance of H.264 in the web video delivery battle. This really will be a solid kick in the pants for Theora, which now seems destined to remain a reasonably niche product, even with direct HTML 5 support from Firefox.

In short order some early comparisons between H.264 and WebM appeared online. Some with more technical detail than others. The debate also began as to whether Google was benevolent or evil. Did WebM contain submarine patents that not even Google were aware of?

Producing WebM video for the masses was the next step. Easy to follow FFmpeg tutorials are available and just a few days ago a major commercial transcoding software vendor announced WebM/VP8 support.

WebM video is already available on YouTube, in experimental form. How long before at least all new YouTube video is transcoded to this format? If WebM quality is on parity with H.264, and the jury is still out on that, what is the unique selling point of H.264? Why would anyone continue to use it? 

There will be a substantial legacy component to overcome. Many people and organisations have invested heavily in H.264 technology, and a move to WebM may represent an operational, although not licensing, cost. However, with Google behind it, many of Big Business' concerns around open source projects may be alleviated.

Adding to this, H.264 video within a Flash player still has significant advantages over HTML 5 delivered video content, in terms of presentation flexibility and perceived security.

H.264 video is of course still dominant for web delivery, just as VP6 and VP7 was in the past. However, WebM is an exciting development with a bright future. Using the collective power of open source development, and no small amount of corporate backing from Google, watch out for WebM to challenge MPEG-LA's codec in the future.


Dirac Schrödinger 1.0.9 Released

By
phillc
on March 9, 2010 9:43 AM | | Comments (0) | TrackBacks (0)
As we were on holiday last week, in the chilly snows of Austria, we almost missed an important announcement regarding the Schrödinger implementation of the Dirac codec.

It has been roughly eleven months since the last Schrödinger release, so this is indeed welcome news.

Don't know what either Schrödinger or Dirac are? Dirac is an advanced royalty-free video compression format, initially developed by the UK's BBC Research and Development team. To quote from the recent release announcement:

"Schrödinger is a cross-platform implementation of the Dirac video compression specification as a C library. The Dirac project maintains two encoder implementations: dirac-research, a research encoder, and Schrödinger, which is meant for user applications. As of this release, Schrödinger outperforms dirac-research in most encoding situations, both in terms of encoding speed and visual quality."

That last sentence is really important. Previous testing by Stream0 showed that while Schrödinger was a much faster implementation than Dirac Research, the quality suffered enormously. If indeed Schrödinger has now surpassed Dirac Research in quality terms, this is exciting news.

Further information regarding enhancements in this release, and plans for a more regular release cycle, are available on the Dirac Video website.

With the increasing acceleration of HTML 5 acceptance, it'd be fantastic to see more browser support for Dirac, alongside Ogg Theora, as an alternative to the currently almost ubiquitous Flash/H.264 combination.

H264 Video Encoding on Amazon's EC2

By
phillc
on October 28, 2009 8:52 AM | | Comments (0) | TrackBacks (1)
Stream #0 recently started looking at Amazon's EC2 computing offering. We created our first public AMI, based on Debian Squeeze, including FFmpeg and x264 pre-installed. Now that we can easily start instances with the necessary basics installed, it is time to compare the relative merits of the different instance sizes that Amazon offers.

EC2 Instances come in a variety of sizes, with different CPU and RAM capacities. We tested the 64-bit offerings, including the recently announced High-Memory Quadruple Extra Large instance.

These 64-bit instances are listed on the EC2 website in the following way:

• Large Instance 7.5 GB of memory, 4 EC2 Compute Units (2 virtual cores with 2 EC2 Compute Units each), 850 GB of instance storage, 64-bit platform
• Extra Large Instance 15 GB of memory, 8 EC2 Compute Units (4 virtual cores with 2 EC2 Compute Units each), 1690 GB of instance storage, 64-bit platform
• High-CPU Extra Large Instance 7 GB of memory, 20 EC2 Compute Units (8 virtual cores with 2.5 EC2 Compute Units each), 1690 GB of instance storage, 64-bit platform
• High-Memory Quadruple Extra Large Instance 68.4 GB of memory, 26 EC2 Compute Units (8 virtual cores with 3.25 EC2 Compute Units each), 1690 GB of instance storage, 64-bit platform

We'll take a closer look later at the in-depth specifications of each below.

Our test file was 5810 frames (a little over 4 minutes and 285MB) of the HD 1920x1080 MP4 AVI version of Big Buck Bunny. The FFmpeg transcode would convert this to H264 using the following 2-pass command:

>ffmpeg -y -i big_buck_bunny_1080p_surround.avi -pass 1 -vcodec libx264 -vpre fastfirstpass -s 1920x1080 -b 2000k -bt 2000k -threads 0 -f mov -an /dev/null && ffmpeg -deinterlace -y -i big_buck_bunny_1080p_surround.avi -pass 2 -acodec libfaac -ab 128k -ac 2 -vcodec libx264 -vpre hq -s 1920x1080 -b 2000k -bt 2000k -threads 0 -f mov big_buck_bunny_1080p_stereo_x264.mov

Setting Threads to zero should mean that FFmpeg automatically takes advantage of the entire number of CPU cores available on each EC2 instance.

FFmpeg revealed the following information about the transcode:

Input #0, avi, from 'big_buck_bunny_1080p_surround.avi':
Duration: 00:09:56.48, start: 0.000000, bitrate: 3968 kb/s
Stream #0.0: Video: mpeg4, yuv420p, 1920x1080 [PAR 1:1 DAR 16:9], 24 tbr, 24 tbn, 24 tbc
Stream #0.1: Audio: ac3, 48000 Hz, 5.1, s16, 448 kb/s
[libx264 @ 0x6620f0]using SAR=1/1
[libx264 @ 0x6620f0]using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle SSE4.1 Cache64
[libx264 @ 0x6620f0]profile High, level 4.0
Output #0, mov, to 'big_buck_bunny_1080p_stereo_x264.mov':
Stream #0.0: Video: libx264, yuv420p, 1920x1080 [PAR 1:1 DAR 16:9], q=10-51, pass 2, 2000 kb/s, 24 tbn, 24 tbc
Stream #0.1: Audio: aac, 48000 Hz, 2 channels, s16, 128 kb/s
Stream mapping:
Stream #0.0 -> #0.0
Stream #0.1 -> #0.1

Ignore the duration, as that's read from the file header, and we only uploaded part of the overall file.

Now to look at how each EC2 instance performed.

m1.large
(Large Instance 7.5 GB of memory, 4 EC2 Compute Units)

Firstly, querying the machine capacity (cat /proc/cpuinfo) returns the following information:

processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 23
model name : Intel(R) Xeon(R) CPU E5430 @ 2.66GHz
stepping : 6
cpu MHz : 2659.994
cache size : 6144 KB
physical id : 0
siblings : 1
core id : 0
cpu cores : 1
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu tsc msr pae mce cx8 apic mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx lm constant_tsc pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr dca lahf_lm
bogomips : 5322.41
clflush size : 64
cache_alignment : 64
address sizes : 38 bits physical, 48 bits virtual
power management:

There's 2 of these cores available. RAM is confirmed as 7.5GB (free -g).

The FFmpeg transcode showed the following:

H264 1st Pass = 11fps - 18 fps, 5 minutes 30 seconds
H264 2nd Pass = 4-5fps, 18 minutes 38 seconds

Total Time: 24 minutes, 8 seconds

m1.xlarge
Extra Large Instance 15 GB of memory, 8 EC2 Compute Units

CPU Info:

processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 23
model name : Intel(R) Xeon(R) CPU E5430 @ 2.66GHz
stepping : 10
cpu MHz : 2666.760
cache size : 6144 KB
physical id : 0
siblings : 1
core id : 0
cpu cores : 1
fpu : yes
fpu_exception : yes
cpuid level : 13
wp : yes
flags : fpu tsc msr pae mce cx8 apic mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx lm constant_tsc pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr dca lahf_lm
bogomips : 5336.15
clflush size : 64
cache_alignment : 64
address sizes : 38 bits physical, 48 bits virtual
power management:

There's 4 of these cores available. RAM is confirmed at 15GB.

The FFmpeg transcode showed the following:

H264 1st Pass = 11fps - 14 fps, 5 minutes 30 seconds
H264 2nd Pass = 6-7fps, 14 minutes 19 seconds

Total Time: 19 minutes, 49 seconds

c1.xlarge
High-CPU Extra Large Instance 7 GB of memory, 20 EC2 Compute Units
CPU Info:

processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 23
model name : Intel(R) Xeon(R) CPU E5410 @ 2.33GHz
stepping : 10
cpu MHz : 2333.414
cache size : 6144 KB
physical id : 0
siblings : 1
core id : 0
cpu cores : 1
fpu : yes
fpu_exception : yes
cpuid level : 13
wp : yes
flags : fpu tsc msr pae mce cx8 apic mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx lm constant_tsc pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr dca lahf_lm
bogomips : 4669.21
clflush size : 64
cache_alignment : 64
address sizes : 38 bits physical, 48 bits virtual
power management:

There's 8 of these cores available. RAM confirmed at 7GB.

The FFmpeg transcode showed the following:

H264 1st Pass = 24-29fps, 3 minutes 24 seconds
H264 2nd Pass = 11-13fps, 7 minutes 8 seconds

Total Time: 10 minutes, 32 seconds

m2.4xlarge
High-Memory Quadruple Extra Large Instance 68.4 GB of memory, 26 EC2 Compute Units

CPU Info:

processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 26
model name : Intel(R) Xeon(R) CPU X5550 @ 2.67GHz
stepping : 5
cpu MHz : 2666.760
cache size : 8192 KB
physical id : 0
siblings : 1
core id : 0
cpu cores : 1
fpu : yes
fpu_exception : yes
cpuid level : 11
wp : yes
flags : fpu tsc msr pae mce cx8 apic mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx lm constant_tsc pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr dca popcnt lahf_lm
bogomips : 5338.09
clflush size : 64
cache_alignment : 64
address sizes : 40 bits physical, 48 bits virtual
power management:

There's 8 of these cores available. RAM confirmed at 68GB.

The FFmpeg transcode showed the following:

H264 1st Pass = 35-38fps, 2 minutes 47 seconds
H264 2nd Pass = 12-15fps, 6 minutes 30 seconds

Total Time: 9 minutes, 17 seconds

What can be revealed from these figures? As expected, the High-Memory Quadruple Extra Large Instance performed best, but not by much. Certainly all the additional RAM didn't make much of an impact, and the time saving is probably really down to the slightly increased CPU specifications. Obviously, over a larger file set this time saving would be more evident.

Let's look at which EC2 instance gives best value for money for this test. Amazon charges per CPU hour, shown below:

m1.large: $0.40/hour
m1.xlarge: $0.80/hour
c1.xlarge: $0.80/hour
m2.4xlarge: $2.40/hour

These are US Dollars and for a US based instance (European instances are slightly more expensive). Amazon has also revealed that there will be a price reduction in effect from November 1st 2009.

Looking at the time taken to transcode our test file, on each instance, reveals the following:

m1.large
Total Time: 24 minutes, 8 seconds
Total Cost: $0.16 ((($0.40/60)/60) x 1448 seconds)
Cost per GB: $0.57 ((1024MB/285MB) x $0.16)

m1.xlarge
Total Time: 19 minutes, 49 seconds
Total Cost: $0.26 ((($0.80/60)/60) x 1189 seconds)
Cost per GB: $0.93 ((1024MB/285MB) x $0.26)

c1.large
Total Time: 10 minutes, 32 seconds
Total Cost: $0.14 ((($0.80/60)/60) x 632 seconds)
Cost per GB: $0.50 ((1024MB/285MB) x $0.14)

m2.4xlarge
Total Time: 9 minutes, 17 seconds
Total Cost: $0.37 ((($2.40/60)/60) x 557 seconds)
Cost per GB: $1.33 ((1024MB/285MB) x $0.37)

Clearly the c1.large instance represents the best value for money, although I was surprised how close behind the m1.large costs were. The additional RAM, and slightly better CPU specifications for the m2.4xlarge instance do not outweigh the much more expensive per hour cost, at least when it comes to video transcoding.

A typical HD file used for broadcast or high end post production purposes is around 85GB for 60 minutes (DnxHD at 185Mbps). Obviously the time taken to transcode this file, to an H264 at 2Mbps, could vary from the actual source content we used, but from the figures above we can estimate that it would cost $42.50 and take approximately 53.62 hours!

Taking into account that these figures may vary for different input and output files, the above should represent a worst case scenario. For example, I would expect an SD MPEG2 50Mbps file to take proportionally much less effort to transcode than a DNxHD 185Mbps HD file. Only a further test will tell......

Is Amazon's EC2 offering worth considering for high end video file transcoding? Compared to the prices charged by Post-Production facilities it is certainly a lot cheaper, as long as you have time to wait for the end result. However, that's the beauty of cloud based computing power - if you're in a hurry just scale up! Keep in mind though, content still needs to be uploaded to EC2 before transcoding can begin, that's going to take additional time and add further cost. 

How Firefox Is Pushing Open Video Onto the Web

By
phillc
on June 20, 2009 9:25 PM | | Comments (0) | TrackBacks (0)
There's a great article called How Firefox Is Pushing Open Video Onto the Web by Micheal Calore over at WebMonkey, dealing with the HTML 5 <video> tag and Firefox's native Ogg Theora support. The piece outlines the technical details of the <video> tag and includes an interview with Mozilla director of Firefox Mike Beltzner and Mozilla director of platform engineering Damon Sicore.

An excerpt from the interview:

Webmonkey: How do you see these factors -- the HTML 5 video tag, putting the Ogg codecs right into the browser, presentation techniques that mimic the plug-in player experience -- affecting video on the web? What's it going to change in six months? Or six years?

Beltzner: In six months, you're going to see more sites like DailyMotion doing things where they detect that the browser supports Ogg and the video tag, and in that case, they're going to give those users an Ogg-and-video-tag-experience.

I think you'll see content sites doing this because they'll have the ability to re-encode their entire video libraries without having to pay any licensing fees. The Ogg Theora encoders are completely license-free and patent-proof. They don't need to worry about which player you've got. They also don't need to worry about which hardware you've got. Ogg Theora will run on Windows, Mac and Linux, or any embedded device or mobile device built on the Linux platform.

Here's a beta example page from DailyMotion demonstrating use of the HTML 5 <video> tag. If you have Firefox 3.5 installed, or a reasonably new version of Webkit/Safari and the XiphQT component install, you should have in browser video playback - Ogg Theora and no Flash player needed.

YouTube's demonstration page here.


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