Archive for December, 2010
Helioviewer.org has been updated this morning to include some recent improvement to the movie generation process. The result of this update is that the quality of the movies that you see on Helioviewer.org has been greatly improved.
While Helioviewer.org has offered High-definition H.264 movies for several months now (encoded using the excellent x264 library), the amount of compression used was fairly high. The result of this was very small file sizes (around 1-5MB), but some noticeable compression artifacts; the effect of which was especially noticeable for larger movies.
For example, the below movie was generated on Helioviewer.org several days ago:
Example 1: In-browser movie before update (download video)
A number of changes were made to the H.264 encoding parameters in order to improve the quality, for example, whereas movies were previously generated using a constant variable bit-rate (-b 2048K), the newer movies use a different rate-control method called “Constant Ratefactor (CRF)” in order to achieve a desired level of quality.
Here is an example of a movie created for viewing in the browser using the new code:
Example 2: In-browser movie after update (download video)
What’s more, the “high-quality” download option is now much higher quality than ever before. Previously, when users clicked on the link below in the in-browser movie that says “Click here to download a high-quality version“, what they got was actually the same movie that was already playing in their browser, but packed in a container format compatible with the user’s operating system. With the update this morning, however, the high-quality download link now points to a separate and visibly higher-quality movie from what is shown in the browser. The high-quality option available now is actually a lossless movie, with respect to the underlying JPEG 2000 data archive used by Helioviewer.org.
Example 3: High quality movie after update (download video)
(Note: If you are having trouble viewing the above video, you can download an MP4 version directly from here.)
Of course, nothing comes for free, and that is true in the case of these improvements as well. The improvements made to quality come at the cost of increased movie filesize. For the standard-quality movie that is shown directly in the browser, the filesize has increased from by a factor of around 1.5-10x with the largest files around 50MB each. The real behemoths, however, are the high-quality (lossless) movies which range from around 50-300MB. It’s a lot, but try watching a few of high-quality AIA movies and you won’t ever want to go back again.
Update 2010/12/31: Thanks to Dark_Shikari on #x264 for some help making sense of some of the many rate control options available when encoding using x264.
Helioviewer.org has been updated to include a number of new features and bug fixes. Although many of the features included in this release have already been available online for some time now, their performance and reliability has been greatly improved during the past several weeks.
Stayed tuned for some exciting new features next week
Helioviewer.org 2.1.0 is a major release which includes many new features and a large number of bug fixes. Major features added include: full support for AIA images, on the fly movie and screenshot creation and a custom resource management and queuing system. Other changes include:
* Overhauled error back-end error handling
* Support for HEK FRM/Event querying
* PHP IMagick used in place of convert when available for better performance (See: http://valokuva.org/?p=40 for more information)
* Custom FFmpeg wrapper used in place of PHPVideoToolkit
* FirePHP support
* Documentation for each back-end module now handled at the module level rather than globally
* IE8 local storage support
* Conversion from tile coordinates to spatial coordinates now handled on front-end
* Removed dependencies on image archive directory structure
* Added a JHelioviewer JNLP generation method so that users can easily jump from Helioviewer.org to JHelioviewer
* Color of image layer timestamps now ranges on a scale from green (near requested time) to red (far from requested time). Absolute difference is used so that it does not matter whether actual image is ahead or behind requested one
* Fixed bug #544338 Edge effects for tiles viewed at higher magnification
* Fixed bug #605412 Helioviewer-generated Flash movies degrade in quality as the movie progresses
* Fixed bug #614558 Use of IMagick#extentImage results in images with incorrect dimensions
* Fixed bug #619944 Movie history panel occasionally stays in viewport
* Fixed bug #312205 Sandbox dimensions are too large for C2 and C3 Images
* Fixed bug #383939 Disable tiling when layer is hidden
* Fixed bug #508723 Check to see if data exists for each source, or provide option to disable a data source
* Fixed bug #605398 Improve JPX request cadence optimization for non-evenly distributed data
* Fixed bug #605411 Fullscreen, etc. button tooltips are hidden by movie/screenshot creation dialogs
* Fixed bug #608265 Chrome appends .html on movies
* Fixed bug #610456 FITS header dialog not updated when image is changed
* Fixed bug #645836 shortcuts for time steps “<” or “>” not working
* Fixed bug #544352 backfill JP2s from SOHO mission up to most recent
* Fixed bug #322857 Sandbox dimensions do not update right away when layers are removed
* Fixed bug #415455 helioviewer logo issues/request
* jQuery imgAreaSelect (0.8 => 0.9.2)
* jQuery jGrowl (1.2.0 => 1.2.4)
* jQuery qTip (1.0 r34 => 1.0 r54)
We now have over 6 million images of the Sun and inner heliosphere available online for everyone to explore. We add approximately 20,000 images a day, and we have been running for about 5 1/2 months so far. Stay tuned for images from different instruments in the near future!