Video services are expected to account for a large proportion of the internet traffic in future wireless networks. With this in mind, acticom also provides solutions for video transmissions over wireless networks. To guarantee efficient bandwidth usage combined with high video quality, acticom is investigating omnipresent and future video traffic characterizations. Bandwidth efficiency is achieved by applying robust header compression and sophisticated scheduling policies. This concept is given creedence by the results of a WLAN based demonstrator for wireless video streaming. 


For traffic characterization acticom uses the newest video standard proposal H. 26L. H. 26L is the result of a coming-together of the ITU- T and ISO/ MPEG. The weight of these two standardization bodies gives H. 26L a high rate of acceptance and utilization. For network performance studies the goal is to evaluate the traffic by means of frame size traces.

For traffic analysis we are grabbing several different video sequences of different content, approximately one hour in duration in YUV format (subsampling 4:1:1). The video format of the sequences will be QCIF (176x144) or CIF (352x288). The video sequences have different content and therefore different dynamic behavior. These sequences are encoded with the reference software of the H. 26L standard group as it is finalized within 2002. We are utilizing different quality or quantization settings to encode. The resulting frame sizes are then statistically evaluated with regard to distributions and long-term memory behavior. We also create trace files for these encoded video streams that are publicly available as we proceed. Utilizing our generated trace files, we want to evaluate the suitability of the current networking technologies available for the transmission of video over wireless links. Additionally we want to investigate possible improvements for the streaming, especially of H. 26L encoded video data for different situations and contents.

We then present the results of traffic measurements for different video encoding schemes. The work is done in cooperation with the Arizona State University and the Technical University of Berlin. 


Program Description

The VideoMeter can be used in several different ways. It is designed to play concatenated YUV-streams in the YUV 4:2:0 format. This format is widespread in the video research and codec development, so having a player could be very useful. The program supports up to 3 sequences that can be played back. As for wireless video transmission evaluation, we named the sequences original, encoded, and transmitted accordingly. The supported formats are QCIF (176x144) and CIF (352x288). Additionally, the difference pictures for the Y component can be calculated, to make the errors visible. These errors can also be expressed in terms of the PSNR, which provides a common measurement for the objective picture quality. The resulting PSNR values and difference pictures are calculated between the original and encoded, the encoded and the transmitted, as well as the original and the transmitted.

The main window provides the view of the yuv sequence as it is played. Additionally the differences and psnr values are shown.

As errors occur, the comparison between the streams will always differ by one or several pictures. In order to make dropped frames freeze in order to compare the right ones, you can provide a freeze file that contains the numbers of frames to be frozen during playback and difference picture / PSNR calculation.

The VideoMeter tool is free for download. Feel free to use the tool for presentation or publication purposes. When doing so, please cite our work and send us a message. Feedback is always appreciated.

The information window (here with all options) shows basic information such as target playback rate, filenames, and loops (if any). Additionally the amount of frames to freeze that were parsed is shown (but not checked whether in playback frame range). The psnr values are shown per current frame and as mean over the played frames. 

Linux (tested on SuSE 7.x, 8, Mandrake 8/9, and RedHat 7.3), X11 (@ 16, 24, or 32 bit display depth), a fast processor for realtime playback at 25/30 FPS. If you are using the videometer tool, please give us a feedback in order that we can improve the features and the performance of the tool.

The information window of the videometer tool.