M-JPEG vs MPEG4

[lillCCTV 0]

Hi ! ok, im a newbie...i apologize

 

Yes, i have also searched the forum, and ive been reading alot about this. But my english isnt perfect...so i just need someone to tell me if im right or wrong about this :

 

If 1st priority is to get best pics out of the DVR ( for identifying etc) then i will use MJPEG.

 

If its more important with remote view, i use MPEG4 ?

 

Is there any of you guru`s still using MJPEG in any projects ?

 

I can also tell you something from my country. We have a department who is certifying CCTV equipment for use in this country. And they write that the DVR should use a compression format like JPEG,MJPEG or wavelet, and not MPEG4,H263,H264 etc..... But my impression is that MPEG is the most frequently used, thats why im getting a little confused...

 

Hope anyone can help, thanks !

[501 0]

The only DVR I have used with Mjpeg was a "Viewgate" model and it was terrible! The resolution and quality was no where near that of geovision even when the Mjpeg was in 640X480 and the Geovision was in 320X240 and Mpeg4.

[lillCCTV 0]

The only DVR I have used with Mjpeg was a "Viewgate" model and it was terrible! The resolution and quality was no where near that of geovision even when the Mjpeg was in 640X480 and the Geovision was in 320X240 and Mpeg4.

 

Well, but it seems like you compare a bad JPEG-DVR with a good MPEG-DVR....i guess that aint fair against the compression format ??

[rory 0]

MJpeg and Wavelet are normally much higher quality for DVRs, but really it depends on the DVR itself .. for example with GeoVision PC cards, their Wavelet does not look much better than the Mpeg4, but its slower.

 

When i used the IView PC DVRs, the Wavelet was better quality than their Mpeg4, noticeably.

 

Personally I would only use H.264 or Mpeg4 ASP, for Remote Video, not actual recording. Mpeg4 is fine, but then it still depends on the DVR as they differ from their modified codecs.

[lillCCTV 0]

MJpeg and Wavelet are normally much higher quality for DVRs, but really it depends on the DVR itself .. for example with GeoVision PC cards, their Wavelet does not look much better than the Mpeg4, but its slower.

 

When i used the IView PC DVRs, the Wavelet was better quality than their Mpeg4, noticeably.

 

Personally I would only use H.264 or Mpeg4 ASP, for Remote Video, not actual recording. Mpeg4 is fine, but then it still depends on the DVR as they differ from their modified codecs.

 

Thanks Rory ! It was kinda like a thought then, but to be sure, i understand i have to test the DVRs up against each others.

[SBTVideoman 0]

As others have rightly pointed out, there is more to DVR image quality than just the compression format. Some of the differences between MJPEG and MPEG4 is that MJPEG compresses each and every image (or frame) individually...so each "digital frame" is a complete image, much like a snapshot from a digital camera.

MPEG4 is a "conditional refresh" algorithm, meaning it compresses groups of frames at a time, and within each group it only digitises the differences between successive frames. Thus not every single "displayed" video image is actually a complete image. This *MAY* (and I stress the word may) be important in some applications where you want or need to play frame-by-frame forwards and backwards...with MJPEG you can do this. It's not generally possible with MPEG4, as the frame sequence is unidirectional - meaning you can step frame-by-frame forwards but trying to do so backwards will generally step back to the nearest full (I or Key frame). You can try this with you DVD player (MPEG2 is similar in this regard to MPEG4) and a movie like the Matrix - try the scene where the chopper crashes into the building and the ripples spread out.

 

There are many "flavours" of MPEG4 with varying image quality. So not all MPEG4 recorders (or MJPEG for that matter) will give you equivalent quality.

 

The same can be said about image security and watermarking. Using Siemens SISTORE DVR's as an example (and this is NOT intended as a plug for Siemens).

SISTORE AX = entry level MPEG4 DVR's have watermarking

 

SISTORE MX = higher level DVR using MJPEG - has Kalagate certified watermarking (basically sufficiently secure to use in a UK court of law).

 

SISTORE CX = high-end MPEG4 DVR/video streaming package also has Kalagate certification...so you can see that the CX uses a different, higher performance version of MPEG4 than the entry-level AX...and the relative costs reflect this.

 

Sorry for the long post...hope it makes sense.

[501 0]

Excellent information. lillcctv, in my post I stated that i had only tested one type of DVR with MJPEG compression, hence I was speking about only one DVR in particular. The differences I saw though were big.

[lillCCTV 0]

Thanks everyone!