H.264 Objections ConsideredBy John Honovich, Published Dec 09, 2009, 07:00pm EST
IQinVision has released a 2 page document with a list of objections and issues when using H.264 compression.
Their claims summarized and our comments:
- "With H.264, we recommend nothing lower than the MAIN profile and that you allow the bit rate to vary (VBR) to ensure delivery of the best quality image." We agree about the benefit of VBR. However, surprisingly many IP cameras do not support VBR for H.264 including Sanyo, Pelco Sarix and Cisco (non-Sarix cameras). The recommendation for MAIN profile is interesting as most MP cameras do not support MAIN profile and those that do (like Pelco Sarix) lack 3rd party VMS support (see our discussion in the Sarix test results). We have not tested a MAIN profile implementation. However, in our tests, we believe that Baseline profile (the lower and more commonly used profile) looks the same visually as MJPEG encoding.
- "Rain and snow will have a significant impact on H.264 bandwidth and storage as it interprets rain and snow as a 100% scene change from one frame to the next."
- "H.264 will serve to compound the problems associated with video degradation and bandwidth increases in low-light environments." We have seen this in some but not all tests with Arecont's low light performance being the most problematic so far.
- "With H.264, scene motion such as trees blowing in the wind can have a dramatic impact on bandwidth and storage requirements." We have seen this in some tests with Axis being one example.
- "A low quality H.264 camera running at 7.5 frames/second (fps) may not capture a single true image (Key Frame) of that normal person, instead producing 15 “estimated” frames, thus making clear video of the subject improbable." We have never seen this as a practical issue. While technically, the images may be produced from estimates, we have not seen the video to be degraded.
IQinVision was late and is still limited in their H.264 MP lineup (see IQ732 overview).
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