Stream Quality/Corrupt Frame Analysis
- Eli Pielet (Writec) (Unlicensed)
Stream quality analysis identifies missing or corrupt video or audio frames from a Feeder to a Broadcaster on a per PID basis. A frame is considered corrupt if the frame’s data is completely missing, partially missing or if it depends on a frame whose data is completely missing or partially missing. For example, if an I-frame is corrupt then it as well as all following P-frames until the next I-frame will be corrupt as well because they depend on the I-frame and previous P-frames. If a P-frame is corrupt, then the following P-frames up to the next I-frame will be corrupt.
In ZEN Master, the percentage of good frames, i.e. not corrupt and not missing, out of the total frames per PID is displayed on a graph. The resolution of the graph depends on the zoom level and is as low as 1 datapoint per minute. To view the stream quality graph, select the History tab when viewing a Source and expand the Stream Quality graph.
In the example above we see 93% good frames in the highlighted area. Corrupt frames, such as the 7% in this example, may be a result of dropped packets during transmission or may occur prior to transmission during the encoding process. Analyzing the non-recovered packets in the network statistics along with TR-101 results can help pinpoint the origin of corrupt frames.