Collecting Information

VP8 vs. H.264

5/20/2010 | Comments: 1

There is a very interesting article about Google's video codec VP8 written by an x264 developer called Jason Garrett-Glaser (aka Dark Shikari) which you can completely read on:

The title is "The first in-depth technical analysis of VP8".

Here are some central statements out of it:

  • Verdict on Intra Prediction: Slightly modified ripoff of H.264. Somewhat worse than H.264 due to omission of i8×8.
  • Verdict on Inter Prediction: Similar partitioning structure to H.264. Much weaker referencing structure. More complex, slightly better interpolation filter. Mostly a wash — except for the lack of B-frames, which is seriously going to hurt compression.
  • Verdict on Transform: Similar to H.264. Slower, slightly more accurate 4×4 transform. Improved DC transform for luma (but not on chroma). No 8×8 transform. Overall, worse.
  • Verdict on Quantization: Lack of well-integrated adaptive quantization is going to be a killer when the time comes to implement psy optimizations. Overall, much worse.
  • Verdict on Entropy Coding: I’m not quite sure here. It’s better in some ways, worse in some ways, and just plain weird in others. My hunch is that it’s probably a very slight win for H.264; non-adaptive arithmetic coding has to have some serious penalties. It may also be a hardware implementation problem.
  • Verdict on Loop Filter: Definitely worse compression-wise than H.264’s due to the lack of adaptive strength. Especially with the “fast” mode, might be significantly faster. I worry about it being too blurry.
  • VP8 is simply way too similar to H.264: a pithy, if slightly inaccurate, description of VP8 would be “H.264 Baseline Profile with a better entropy coder”.
  • Before I tear the encoder apart, keep in mind that it isn’t bad. In fact, compression-wise, I don’t think they’re going to be able to get it that much better using standard methods.
  • The encoder and decoder share a staggering amount of code. This means that any bug in the common code will affect both, and thus won’t be spotted because it will affect them both in a matching fashion.
  • Google has chosen Matroska for their container format.

I definitely recommend reading at least the "Addendum C: Summary for the lazy".

Mozilla Firefox and H.264

5/ 6/2010 | Comments: 1

I just read an article related to H.264 patent licensing issues going on at the moment. There was one sentence which blew me away with truth:

"If H.264 continues to evolve and gain widespread support in the market, Mozilla may eventually have to make an impossible decision between idealism and compatibility, and we're not even going to try and predict how that one will turn out -- remember, we're having this H.264 conversation right now because it's in line to replace Flash video, which is arguably even less free and open."

Change exif timestamp of JPGs with Exiv2

5/ 3/2010 | Comments: 1

I usually rename my JPG photos with the help of the Exif timestamp ("DateTimeOriginal", to be precise). It so can happen that I can't use this timestamp if I once forget setting the internal clock of my camera - because then, the timestamps aren't correct, obviously.

Exiv2 is a useful program that can quite easily change exif timestamps - among other things.

So in a nutshell, change the timestamp as follows:

exiv2 -a 00:01:00 ad test.jpg

This would add one minute to the timestamp of test.jpg. Of course you can also subtract a certain amount of time: Just write a minus sign in front of the timestamp.

Moreover, you can change the filename of a JPG according to the Exif timestamp like this:

exiv2 -r "%Y-%m-%d - %H-%M-%S - :basename:" mv test.jpg

This syntax keeps the original filename in the newly created filename.

Change some IPTC-Data as follows. Instead of Copyright there are other field names like Byline, Caption, Keywords...:

exiv2 -M "set Iptc.Application2.Copyright Some copyright message..." mo test.jpg

Display all Exif, IPTC, XMP data of the picture:

exiv2 -p a pr test.jpg

Rebuilding the site

5/ 2/2010

Man, today I had to rebuild my whole website because I moved it from a subfolder to this actual domain folder. After that the system somehow got confused with the new folder structure... I surely could have solved it, had I only known more about the internal PHP file structure. Well, in the end I got it working again...

Deshake a video of a Panasonic Lumix TZ7

5/ 1/2010 | Comments: 4

I just tried deshaking a video filmed with a Panasonic Lumix TZ7 - and I succeeded! smiley

The source video from the TZ7 is called something.mts

My steps were the following:

  1. Load the source video into Avidemux
  2. Leave the video track as it is ("Copy") and change the audio track to "mp3" (e.g. CBR, 128kbps). I unfortunately had to do this because otherwise Virtualdub doesn't do the next step... Set the output container to "AVI". And what was important for me: Set the appropriate frame rate of your video under Video -> Frame rate.
  3. Load the newly created AVI into Virtualdub
  4. Add the previously installed (copied) Deshaker as a filter (Video -> Filters -> Add) and set it to "Pass 1"
  5. Execute File -> Preview filtered... and wait!
  6. Set the Deshaker to "Pass 2" and File -> Save as AVI
  7. As I didn't tell Virtualdub any compression format or codec it outputs a raw AVI video. So now load it once more into Avidemux and set the video track to MPEG-4 AVC (x264), copy the audio track and let the container be AVI. At this point, I will surely not delve into the depths of the possible x264 configuration options!! (Though I could, as this was the subject of my university diploma thesis. wink )
  8. One weird thing was that after loading the deshaked raw AVI into Avidemux again (step 7) I saw the video vertically flipped!! So I had to apply a vertical flipping filter, too.....

Well, those steps did the trick for me!

By the way, my software versions were: Virtualdub 1.9.9, Avidemux 2.5.2, Deshaker 2.4, and I worked with Windows 7.

Im twittering

4/30/2010 | Comments: 1

Finally, I'm registered on twitter and trying out some of it. I'll see what good comes out of it...

Check out my twitter page:

New youtube videos


Some brand new videos are online where I was playing some music alone and also with my brother. The recording took place on my birthday last saturday.

Check them out on my channel:

The first entry!

4/30/2010 | Comments: 1

Well, doesn't seem too bad, this blog here, what do you mean? Hm....

At least this would be a possibility for me to write some things...

Yay, let's go!!!