WURFL Test Suite: Testing Video with Alembik by Jakub Danilewicz, Dani Alonso (Kimia) and Luca Passani (editor) Important Note: Alembik is an open-source project sponsored by Kimia Solutions - the mobile software company from Spain. Its primary goal is to bring the power of free media processing and web rendering to every developer and company. Please visit the Alembik web page to learn more details. Alembik Tester Application application allows testing of video playback (download) and streaming as well as audio playback (download) for any mobile device. Testers access the application through its WAP interface. No prior knowledge of supported formats and parameters for a given device is required to perform the tests. Application features The application is an easy and practical tool for discovering the audio and video capabilities of any device. Developers can learn the discovered capabilities and at the same time help to provide the new information into the WURFL DB, which eventually is going to be made available to everyone. At any moment users may view and download the log of the tests they have performed. All the logs are periodically analysed by WURFL personel and hence the new video/audio information finds its way into the WURFL repository. The selection of possible formats is simple and straight-forward. The testers are free to adjust the parameters of the video/audio content, which is instantly transcoded according to the chosen set of values and then promptly served. After view/listening to it a tester can produce a log stating whether his chosen "parameters set" suits the device he is examining at the moment. The system also provides a separate module for WURFL administrators to study and adjust the log data, before it gets submitted to the WURFL DB in the form of a WURFL patch file. The application offers a variety of formats for testing. Of course, not all the formats are supposed to be reproduced properly (some may even fail completely!) on every device. Some property values may appear to be out of acceptable scope or a given codec may simply not be supported by a given device. Please note that the application does not support all possible formats; we are currently working on enabling the H264 codec. However, the most common ones are supported: VIDEO AUDIO DOWNLOAD STREAMING DOWNLOAD STREAMING 3gp 3gp mp3 - - 3g2 - - amr - - mp4 mp4 wma - - mov - - aac - - All the content reformatting is provided behind the scenes by Alembik Media Transcoding Server, which is a Java (J2EE) application providing transcoding services for different media types (image, audio, video, etc). User guide The Alembik Tester Application is available at: http://video.wurflpro.com/tester/ (please type it into your mobile device browser) Upon entering the application the tester has to make two initial choices about the testing domain: Video vs Audio Download vs Streaming NOTE: the audio streaming is currently disabled (Alembik does not support this feature at the moment). Video section After selecting the video domain (either download or transcoding), the tester is presented with a wizard-style sequence of pages, which offer the selection of all the audio/video properties of a sample video file to be viewed. The first page asks the tester to choose a desired video architecture (also known as the container). The next screen allows him to choose a particular video and audio codec (out of the ones the selected container supports). At the third step there must be selected a relevant video codec level. Eventually the tester needs to pick a preferred final configuration for both audio and video codecs; each set of possible video codec parameters is derived from the previously selected level, while a list of possible audio configurations is provided by WURFL media library. Each video set is presented in the format: "bit rate; screen size; frame rate"; audio parameters follow this pattern: "bit rate; sampling rate; channel". Upon completion the test wizard forwards the tester to the final screen, where he may review the summary of the selections he has made and play the transcoded video file through a provided link. Additionaly, after having played the video on his device, the tester may share his experience by contributing his quality evaluation to the application log. For that there are "OK" and "Bad" buttons available to choose whether his playback/streaming experience has been acceptable or not (i.e. whether his device supports the chosen configuration or not). Audio section Testing of the audio domain has a different wizard flow. There the tester application starts with a page, which presents a transcoded audio file based on parameters evaluated by Alembik and WURFL repository (if available). Additionaly, two other content versions are offered below, with a slightly increased and reduced bit rate value (+-10%). As it has been explained in the video section above, the tester can use "OK" and "Bad" buttons to share his playback experience with WURFL DB administrators. However, if he finds that the format of a transcoded file is not supported by his device (it is rejected), he should mark it as invalid by pressing the "Invalid data" button instead. This means that WURFL repository contains incorrect data on the device model he is using. In case of doubts over the "bad vs invalid" decision or any question concerning the support for non-default formats, the application offers a more fine-grained selection of "own audio characteristics". There the tester has to choose a desired audio codec first and then pick a particular bit rate from a displayed list. There are seven bit rate values for each codec, evenly distributed within [-50%, +50%] range based on Alembik default bit rate value. After having selected all the required values, the tester is presented with a audio content page similar to the ones explained above. Administrator guide The administration module gives the opportunity to view and process the application logs produced by testers. The module consists of three different sections. First page allows any user to view the "good" logs (which are produced by testers satisfied with a transcoded media file). The second one allows viewing the bad logs (submitted by tester who could not play a transcoded media file). Both offer the generation of reports in the form of a CSV file and an XML "wurfl_patch.xml" file. The last page lets the user modify and delete submitted log entries and that is why it requires user authentication. This web module is reserved for WURFL administrators only and it is supposed to be accessed with desktop browsers. Good Logs: URL: http://video.wurflpro.com/tester/goodlogs.do This page presents the list of the "ok" logs submitted by testers. It gives access to both CSV and XML reports for any log. Bad Logs: URL: http://video.wurflpro.com/tester/badlogs.do Feedback and questions Feedback and questions about the Alembik Tester Application should be sent to the WurflVideo mailing list: http://tech.groups.yahoo.com/group/wurflvideo/ Share your feedback and suggestions with us!

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