james.wilson Posted January 10, 2009 Posted January 10, 2009 agreed, but will the bitrate still go high enough to compete with jpeg with a lot of scene change? securitywarehouse Security Supplies from Security Warehouse Trade Members please contact us for your TSI vetted trade discount.
digitalwitness Posted January 10, 2009 Posted January 10, 2009 My appologies Redbull if I misinterpret the question but if you are asking if from my experience can H.264 achieve similar picture quality to JPEG, then yes it can. Ofcourse H.264 is not better in every circumstance than JPEG but in the majority of applications, H.264 is the better compromise due to its very efficient bitrates with very little movement which negates the need for on screen motion detection which is import particularly for outside scenes. My confusion with the question comes with the focus on a particular bitrate level, surely that depends on how the DVR applies the H.264 or JPEG compression technologies as one bit rate for one h.264 even versus another h.264 may not equal the same picture quality (the use of prefilters for example).
kensplace Posted January 12, 2009 Posted January 12, 2009 What I find annoying, is that consumers purchasing tv hard disk recorders get better quality than almost every dvr I have seen. OK, the storage length is not that high, but the quality of the picture is fantastic on consumer level stuff designed for recording eastenders etc. It really puts most dvr's to shame. And at the end of the day, dvr manufacturers could be using this technology, as it must be cheap enough if you can purchase them for them home cheaply. They would need to add dual codec support for remote viewing though, as the home stuff often uses mpeg.
james.wilson Posted January 12, 2009 Posted January 12, 2009 My appologies Redbull if I misinterpret the question but if you are asking if from my experience can H.264 achieve similar picture quality to JPEG, then yes it can. Ofcourse H.264 is not better in every circumstance than JPEG but in the majority of applications, H.264 is the better compromise due to its very efficient bitrates with very little movement which negates the need for on screen motion detection which is import particularly for outside scenes.My confusion with the question comes with the focus on a particular bitrate level, surely that depends on how the DVR applies the H.264 or JPEG compression technologies as one bit rate for one h.264 even versus another h.264 may not equal the same picture quality (the use of prefilters for example). digital witness i do understand the technology and im hoping you are misunderstanding me slightly. What im meaning the highest setting on any Mpeg (whatever codec) recorder i have seen is not able to deal with high scene changes without blocking. For example (using the dm digi sprite here) i can set jpeg upto say a 45Kb file size that will deal with full scene chnages no issues, but setting an mpeg up to 'super fine' or whatever the setting is, cannot compete with this. If the scene change is minimal then this obviously doenst come into play. The problem is made worse at night when cameras up the gain and you end up with noise in the image. Jpeg is far better here as an mpeg unit see a full scene chnage every frame and any benefit to conditional refresh IMHO is lost. Maybe varible bit rate is the answer with the max bitrate upto say 15 Mbit/s? What is the highest bitrate available on one of your machines for example? securitywarehouse Security Supplies from Security Warehouse Trade Members please contact us for your TSI vetted trade discount.
Joe Harris Posted January 13, 2009 Posted January 13, 2009 The problem is intrinsic with how MPEG functions. Sadly, in almost all CCTV installations it is the part of the scene which is moving which is the most important part of the image. The moving image however is obviously most prone to artifacts due to the method of compression. There is still a viable place for improvements in compression and standardisation on one of the many, many available formats.... If only it would happen... 'J
digitalwitness Posted January 13, 2009 Posted January 13, 2009 The Penny dropped for me Redbull, I did not realise you were using a DM Digi Sprite. The bitrate/s on our machines is not a setting and varys depending on the resolution, quality settings and frames/s and continuously changes depending on the amount of scene change, there is no max bit rate or at least a user selectable one. Agreed that under certain circumstances such as full scene change that codecs like MPEG4 and probably H.264 can be less effecient than JPEG and hence their benefit may not be realised in such an application if its 24/7. We have not yet tested a H.264 machine that would be closer to the DM sprite budget so a more direct comparison cannot be performed but in the mass market I believe H.264 can offer a real alternative.
Joe Harris Posted January 13, 2009 Posted January 13, 2009 I agree with regards H.264 variants. The issue still comes back to the level to which the standard is adhered to by manufacturers. Note that I said 'variants', the very reason being such a vast difference in the extent to which the standard has been implemented. Just occasionally manufacturers need to take a step back from their products to realise that all the extra features in the world are great, but if it doesn't acheive its main objectives then it defeats the object entirely. The times when I have seen takeovers with dramatically poorly implemented systems which we have had to bring up to speed. (Often little or no extra equipment just a more effective installation 'J
Doktor Jon Posted January 14, 2009 Posted January 14, 2009 Just occasionally manufacturers need to take a step back from their products to realise that all the extra features in the world are great, but if it doesn't acheive its main objectives then it defeats the object entirely. I couldn't agree more TTG
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