Video Quality

Tips, tricks and frequently asked questions
kiboost
Posts: 596
Joined: 21 Jun 2013, 09:27

Re: Video Quality

Post by kiboost » 06 Dec 2016, 14:49

PAL is 25fps (based on 50Hzh)

Anyway, Netatmo should let the user set bitrate, being on 500Mbs fiber connection I prefer quality over size !
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Una Real
Posts: 304
Joined: 04 Dec 2012, 23:16

Re: Video Quality

Post by Una Real » 06 Dec 2016, 14:57

Yes, that's what I said at the end of my post - 25fps - but thought maybe VLC was showing it as 24fps. Are you in a PAL country?

I agree Netatmo should let the user set bitrate. Maybe that's further down the road for them. They seem to be having problems just implementing things as they should be now without needing to further complicate the picture with additional features.

Tiamat1701
Posts: 55
Joined: 24 Nov 2016, 02:06

Re: Video Quality

Post by Tiamat1701 » 06 Dec 2016, 18:28

Bitrate isn't the whole issue here. You can have 10 Mbps and still have crappy video quality. Quantization, key frame intervals, etc also influence video quality.

Una Real
Posts: 304
Joined: 04 Dec 2012, 23:16

Re: Video Quality

Post by Una Real » 06 Dec 2016, 18:42

Absolutely agree. It gets even more complicated than that. For example, there's VBR and CBR. However, I doubt there are many reading this who care to get that granular. So talking about the simplest and most obvious factors that influence basic video quality seemed to make sense.

There are a lot of "tricks" that can be used to make the human eye believe it's seeing more detail than is actually present in a video. More accurately, to not realize what's missing. But you can only take that so far. You can't add more detail than the data rate cap allows. And 3 Mbps is not a substantial enough bitrate to yield quality video under most circumstances (i.e. any amount of detail or movement) at 1920x1080 resolution.

I might add that the size and quality of the screen you're viewing on has a big influence on perceived video quality. Something that looks really good on an iPhone may not look so hot if AirPlayed to a 60" TV.

kiboost
Posts: 596
Joined: 21 Jun 2013, 09:27

Re: Video Quality

Post by kiboost » 06 Dec 2016, 20:39

They could simply offer four presets, corresponding to connection speed (low/standard/medium/high). The camera itself could even make a small speedtest.
I just hope the camera itself have enough process power to encode it fast enough. And not having h264 make me think it isen't the case ...
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Una Real
Posts: 304
Joined: 04 Dec 2012, 23:16

Re: Video Quality

Post by Una Real » 06 Dec 2016, 20:57

From what I understand, the live stream quality (bitrate or resolution or both?) is adjusted according to connection speed. However, in the Help Center they say the following about downloaded video:

"When you download a video, the resolution is always Full HD, no matter the speed of your internet connection."

Problem with just saying "Full HD" is it tells you nothing about video quality. That term is commonly accepted to merely indicate the resolution is 1080 (versus 720, which is often referred to as HD). It says nothing about the actual quality of the video at that resolution. As pointed out previously, it has the possibility of not looking too good.

So their entire explanation about video leaves a lot to be desired.

kthemall
Posts: 74
Joined: 31 Oct 2016, 12:59

Re: Video Quality

Post by kthemall » 08 Dec 2016, 21:00

just took a look at the details of one of my ftp-downloaded videos.

Bitrate 3000kBit/s on 24fps this is for sure too low for a good quality video.

positive: the audio quality is as mentioned in the firmware information, much better than before. thx for that


any ideas on the videoquality netatmo?

thx tom

Una Real
Posts: 304
Joined: 04 Dec 2012, 23:16

Re: Video Quality

Post by Una Real » 09 Dec 2016, 13:10

Just got my unit set up and have some rather lengthly comments about the video quality along with some pure speculation about some inconsistencies that have been bugging me.

Am going to begin by saying the video quality is “adequate” for my purposes. So I’m not upset about it in that regard. It serves the purpose. And if I’d never read anything about the Presence’s video quality before having actually seen it, I wouldn’t be overly disappointed. But I’d also be far from impressed.

Having been in the forefront of the desktop digital video revolution and then a video producer for over 20 years, I’ve pretty much seen and worked with it all. From the very earliest blocky codecs at a whopping 160x120 resolution to shooting and producing in 4K. And I fully understand that the perception of video quality is highly subjective.

About Netatmo’s claims for the video quality of Presence:

“STUNNING VIDEO QUALITY AND ZOOM
Videos are recorded in excellent Full HD quality.
Pinch-to-zoom into the video to see every detail.”

Having now actually seen the video the Presence records, I must say that these claims are nothing short of ludicrous. The only thing “stunning” would be seeing the actual quality after having read these outrageous claims about “excellent” Full HD quality. There is nothing even approaching excellence here. And I can’t figure out why anyone would want to pinch-to-zoom unless it would be to get a better look at every detail of every blocky pixel. Zooming has little to no impact in terms of a better understanding of what you’re seeing. And, in many cases, only makes it worse.

I confirmed that my Presence is recording 24fps at a bitrate of around 3 Mbps. So the actually quality (or lack thereof) is not at all surprising. In fact, at only 24fps versus the 30fps I had read about - one might expect the quality to be slightly better at the lower framerate.

I would place Netatmo’s description of the video quality (quoted above) in the same category as the customer reading about and expecting a 16 GB card and instead receiving only an 8 GB card. Which brings me to the following admittedly pure conjecture - and here’s where my fascination with multiple inconsistencies comes into play. Almost without exception, the many Presence reviews I've read stated the video quality was very good to excellent, it was Full HD at 30fps (not 24fps), and the unit came with a 16 GB card. Hmmm. Strange there would be so many discrepancies between the reviews and reality. However, what if those reviews were indeed accurate when describing the units supplied to the reviewers? What if there was a decision made prior to general release to instead go with an 8 GB card? But that would only allow for half the amount of video on the card. Customers might complain about the card holding too little. What to do? Well, the logical thing would be to reduce the size of the recorded videos. And lowering framerate and bitrate would do the trick. Unfortunately, video quality suffers at lower bitrates. Hmmm. Just saying. I am sometimes accused of having an over-active imagination. ;)

Tiamat1701
Posts: 55
Joined: 24 Nov 2016, 02:06

Re: Video Quality

Post by Tiamat1701 » 10 Dec 2016, 04:25

A better question is: why is the Presence a 4 MP sensor when it only takes 1920 x 1080 = ~2 MP?

My guess is it downsamples a 4 MP image to 2 MP in order to achieve a higher PPI, which in turn could result in better low light performance, but at the cost of sharpness. Just a guess ...

Una Real
Posts: 304
Joined: 04 Dec 2012, 23:16

Re: Video Quality

Post by Una Real » 10 Dec 2016, 10:34

Tiamat1701 wrote:A better question is: why is the Presence a 4 MP sensor when it only takes 1920 x 1080 = ~2 MP?

My guess is it downsamples a 4 MP image to 2 MP in order to achieve a higher PPI, which in turn could result in better low light performance, but at the cost of sharpness. Just a guess ...
Interesting point and certainly a possibility.

In my previous posts, I've talked about the 24fps framerate, and it may have appeared I considered that a negative. So, wanted to add that I have nothing against 24fps video. In fact, most of the footage I've shot in the past 6 years has been shot at 24fps. I have no complaints about that framerate in principle. Just wasn't expecting to see it in the Netatmo footage after reading it would be 30fps. One more surprise.

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