"Hidden cost of H.264" - Do you agree with this video?

[kaon 0]

http://www.youtube.com/watch?v=vQaTjSs0cvc

This video looks like it's done by Mobotix marketing dept.

 

What they claimed was surprising to me, because I had assumed that H.264 streams from IP cameras do not need to be decoded in order to be recorded.

 

From what I understand, decoding the stream at the NVR would only be done if there are some video analytics to be done, or during "live viewing", or during playback.

An NVR that decodes H.264 and then re-encodes for recording, is poor design, because it wastes CPU cycles.

A sensible NVR would accept H.264 streams and at most repackage the stream in its own container format, this should not be CPU intensive.

 

Am I mistaken?

[amirm 0]

Your observation is correct. Recording does not involve decoding. However, displaying does. I suspect the calculators they used for MPEG-4/MJPEG took into account the fact that someone may be viewing all of those streams on screen. The system they show for Mobotix does not include any station to view said streams. So the whole comparison is improper.

 

That said, MXPEG is much faster to decode than H.264. The drawback is tiling distortion. MXPEG works like MJPEG except that it will not transmit a block it thinks has not changed. The block that has changed gets compressed similarly to JPEG. If there is motion in one block, that would be transmitted and you will see the borders of that block at times. For security applications, that may be acceptable.

 

H.264 has its own set of issues. Even though it looks good for video, it does not always look good when you freeze an image. In-between frames will have distortion that they would not if you had used MJPEG or MXPEG.

 

As cost of H.264 encoding heavily declines (especially in 2 megapixel units), the advantage of MXPEG keeps declining.

 

As to IPacadamy, they provide training for Mobotix so they are either under direct control of them, or make money from selling services to their customers. That said, their work outside of this piece is pretty high quality. I read their newsletters and it has good information not available from Mobotix itself!