Streaming Video-How it works?

Boomyal

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We recently hooked up to Netflix Streaming video. The few times we used it, it worked well. A couple of times the video stopped to catch up? It was not a big deal.

Tonight, (Sunday) the pauses were intolerable. The picture stopped every few minutes and took as long as 30-45 seconds to resume. We finally shut it off.

My question is this. Unlike someother things on the internet, these videos do not seem to 'buffer' when everything is up to speed. That is to say, the 'broadcast' does not run faster than the viewing speed.

Is this true? If so, is it the nature of the 'broadcast' or is it a limitation of the device receiving it. In this case we are using a Sony BluRay/DVD unit to receive the streaming video.

If this situation persists, Streaming Video is not worth the effort nor the cost.

What say all you cyberspace gurus?

ps, not sure if I used all the right terms to describe this.
 

MTboatguy

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Re: Streaming Video-How it works?

Sounds like your incoming line has an excessive amount of traffic this evening, the quality of video depends on how much bandwidth is being used in your area, your ISP, may have had some difficulties this evening, even though these companies advertise video on demand, their quality is still dependent on how much traffic is going through those lines..I had netflix's for about a week and came to the conclusion, that our back bone is just not strong enough where I live to make it worth it..you can only pump so much information through those lines.

Based on your information, you are In SW Washington and they currently have some difficulties going on due to quite a bit of quick growth going on in that area. My Dad lives out in Salmon Creek and even with a comcast cable connection we could not get netflix's to work worth a darn, just to many people online in that area right now.
 

Cofe

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Re: Streaming Video-How it works?

It all depends on your internet speed. If a lot of people are on the same internet system as you, then speed goes down. Picture your internet as a pipe of a certain size coming into your house. The more neighbors that you have on the same pipe line, will limit the amount of product you get. When your neighbors are not using their product, then you get more product. "bandwidth"
 

Boomyal

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Re: Streaming Video-How it works?

I assumed this all to be the case. I am sure that Comcast does not appreciate streaming video. It would be a constant flow as long as the movie is playing whereas if you are just on the internet you may have large downtimes as you view a page.

One of my questions, however, was related to 'buffering' (if that is the right term) Some videos that you watch on the internet will continue to load onto your ram even when you are paused OR sometimes it is apparent that the incoming stream is faster than the view speed.

I guess this is not the case with Netflix type streaming? Would this be because the BluRay/DVD unit has no RAM or is it just the nature of the 'stream' broadcast?
 

MTboatguy

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Re: Streaming Video-How it works?

I would say if probably depends on your blu ray machine, on my Dad's system we had a 1 gig hard drive hooked up to allow buffering and it still did not work like it should have, now with a DVR in place it might be different, I have never tried one with a DVR hooked up.

You might get a hold of netflix's customer support and talk with them about the problem you had, and they might be able to direct you to a solution.
 

mscher

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Re: Streaming Video-How it works?

I assumed this all to be the case. I am sure that Comcast does not appreciate streaming video. It would be a constant flow as long as the movie is playing whereas if you are just on the internet you may have large downtimes as you view a page.

One of my questions, however, was related to 'buffering' (if that is the right term) Some videos that you watch on the internet will continue to load onto your ram even when you are paused OR sometimes it is apparent that the incoming stream is faster than the view speed.

I guess this is not the case with Netflix type streaming? Would this be because the BluRay/DVD unit has no RAM or is it just the nature of the 'stream' broadcast?

All streaming video uses buffering, where a certain amount of data is held in RAM. Your viewing program, reads out of the buffer continously, while the data that is downloading, attempts to keep the buffer full. If more data is downloaded than the buffer needs, the excess data will be written to hard disk and then copied to the buffer, as needed.

When your buffer is out (and nothing is written to hard drive), the video stops, until enough new data is downloaded and written into the buffer, to start viewing video again.

I am actually amazed that Netflix and others are actually selling this as a wide-scale viable service. Youtube videos etc., are already dog-slow and they are small files, running in the lightweight flash format.

The Internet only has so much bandwidth and the thought of millions of people, watching on-demand, real time, streaming videos of movies and TV, without major performance problems, is ludicrous at best.

The only way I could see this as truely viable (and reliable), is if the whole movie or tv show, is downloaded to the hard drive first. Then, the only "streaming" that will need to take place, is between the hard drive and the program buffer, which then will work fine.

But then, who wants to wait? ;)
 

rogerwa

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Re: Streaming Video-How it works?

THere has been no mention of your ISP speed. AT home I have a 7mb down and 900K up connection. My Netflix is built into my BR player and it senses the availabe download speed and selects the Bit rate from there. depending on what is going on in the house, it will vary. But rarely do I ever get bufffering pauses.

ARe you doing this over a WIFI connecton or hardwaired to the router? You can also go to DSLREPORTS.COM and run speed tests to see what your actual ISP performance is.
 

Boomyal

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Re: Streaming Video-How it works?

rogerwa, I am running all wired from the modem to the router, to the switch then back thru the new wall outlets to the bluray/dvd. I did not see any speed test programs on the link you posted but I am sure that it is running faster at this moment than it was for the evening I posted.

I have watched a couple of things since and only had a few short buffering episodes.
 

ajgraz

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Re: Streaming Video-How it works?

Try www.speedtest.net to find your download and upload speeds.

With Cox Cable I get 20-24 Mbps download on ethernet hardline connection (how my Blu-Ray is connected), and I still occasionaly get pauses in Netflix, especially in that 7-10pm period when everyone else is streaming or on the net.
 

mscher

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Re: Streaming Video-How it works?

I do not see how this affects anything viewed via the bluray/dvd and the TV. It seems only to apply while watching the vid on your computer????

I did some Google and it appears that some Blu-Ray DVD players are being made, with Netflix account functionalty added, meaning that they will connect to the Internet and process "instant" ;) Netflix movies/TV shows.

The two viewing functions (Blu-ray DVD/Netflix) are still separate (luckily).

I did not see where Netflix offers any Blu-Ray movie download options, which is a good thing, if they plan to keep the Internet from stopping completely.
 

jlinder

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Re: Streaming Video-How it works?

I did some Google and it appears that some Blu-Ray DVD players are being made, with Netflix account functionalty added, meaning that they will connect to the Internet and process "instant" ;) Netflix movies/TV shows.

The two viewing functions (Blu-ray DVD/Netflix) are still separate (luckily).

I did not see where Netflix offers any Blu-Ray movie download options, which is a good thing, if they plan to keep the Internet from stopping completely.

Netflix does have the ability to stream HD, which is what you are thinking of when you talk about Blu-Ray. (Blu-Ray is a format for a disk that allows you to have enough space on the disc to store a move in HD).

Netflix also does a check of your network speed and will set up the bit rate accordingly. When I download via my Blu-Ray player (it supports direct Netflix) the first thing it does it to check the network speed.

ajgraz - I doubt you are really getting the 20-24Mb/s you think you are getting. ISPs typically will give you the high speed for the first second or so, then for a sustained stream they knock it down to something slower (Comcast calls it boost). If you used one of the speed test web sites to test your speed they recognize it and will give you the high speed for the whole test. Makes people think they are getting more than they really do for big downloads.

mscher - the article tells you how to change the bit rate of the video. At a lower bit rate with a constant buffer size (in bytes) you effectively get a bigger buffer but its is not the same as changing the buffer. It will give you a higher resistance to halting video but it reduces quality.
 

bassman284

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Re: Streaming Video-How it works?

Interesting. I haven't run the speedtest for a long time and on the first try, I got a 292ms ping! Ha! Test was about normal for my DSL - 4.8 down and 0.62 up. The nice thing about DSL is no nodes to get crowded. I know people around here who switched from cable internet to DSL because it was functionally faster.

{edit} Guess the topic was Netflix streaming was actually the topic.

I don't bother with my desktop because it usually stalls. this puter is about 9 years old and only had half a gig of ram the last time I tried. Also running a wireless adapter on 1.0 USB. I also have a year old laptop that has had no problems the few times I've streamed.
 

jlinder

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Re: Streaming Video-How it works?

If you really had a 292ms ping you would not be getting 4.8Mb/s download. Has to do with latency and buffers on the computer and gets involved.

I just tried a test and had about 8Mb/s local but with a far away site with a 278ms ping it was down to 1.65Mb/s. This was with a MAC - tests I have run on Windows would give an even lower speed. (again, fairly complex explanation).
 

mscher

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Re: Streaming Video-How it works?

If you really had a 292ms ping you would not be getting 4.8Mb/s download. Has to do with latency and buffers on the computer and gets involved.

I just tried a test and had about 8Mb/s local but with a far away site with a 278ms ping it was down to 1.65Mb/s. This was with a MAC - tests I have run on Windows would give an even lower speed. (again, fairly complex explanation).

The "ping" utility is not indicitave of network bandwidth capacity measurement.

It's only purpose is to measure (round trip) how long it takes, for a test data packet to be sent from one host to another host and the acknowledgement packed received, by the originating host.

One could be on a very high speed network segment and a ping packets sent to an overloaded host server, would return a very slow ping time. Overloaded individual network segments and routers will slow ping times also. "Internet speed tests" utilities use ping (as well as FTP) in their code, but use other calculations to determine upload-download speeds, which are not overly accurate, IMO.

"TRACERT" *tracert -d "domainname" is a better command line utility for internet speed problems. It will tell you where your slow segments are, not that you can do much about it. ;)

A 292ms ping time stinks. It might be all right if you are using a modem. ;)
 

jlinder

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Re: Streaming Video-How it works?

The "ping" utility is not indicitave of network bandwidth capacity measurement.

It's only purpose is to measure (round trip) how long it takes, for a test data packet to be sent from one host to another host and the acknowledgement packed received, by the originating host.

One could be on a very high speed network segment and a ping packets sent to an overloaded host server, would return a very slow ping time. Overloaded individual network segments and routers will slow ping times also. "Internet speed tests" utilities use ping (as well as FTP) in their code, but use other calculations to determine upload-download speeds, which are not overly accurate, IMO.

"TRACERT" *tracert -d "domainname" is a better command line utility for internet speed problems. It will tell you where your slow segments are, not that you can do much about it. ;)

A 292ms ping time stinks. It might be all right if you are using a modem. ;)

I agree. Ping does not equal speed. Unless you consider latency and the speed of light.

Standard file transfer protocol uses something called TCP. TCP is a guaranteed delivery. The sender keeps the data in a buffer until the receiver acknowledges it. If it is not acknowledged as valid the sender will try to resend up to 3 times before the transfer fails.

The problem is latency (and the speed of light). With high enough speed/too long of a round trip (ping time) the senders buffer will fill up before you can acknowledge the packets. As a result the sender will halt sending until the receiver acknowledges packets which free up buffers. This stop and start reduces the total transfer speed.

With a typical windows machine you can get up to about 20Mb/s over a 700 mile link, about 8Mb/s over about 2500 mile link, etc. (Yes, I have run a whole lot of tests on this). With a 292 ms ping time you are way down. Go to speedtest.net and pick a server on the other side of the world and try it.

To confuse matters even more while normal internet traffic uses TCP - a guaranteed delivery protocol - streaming video video uses UDP. UDP does not give a guaranteed delivery. The sender pushes it out and if the receiver misses it or it is corrupted too bad. Hence no buffers to fill up.

This works for streaming video in part because if you miss the packet too bad, the video moves on. But the speed tests use TCP, not UDP, hence the reason you cannot get high speed with 292ms ping time.

Sorry, I warned you that it was rather involved, that is why I did not go into too much detail at first. Just be glad I did not go into details about modifying buffer sizes on the OS, or network acceleration techniques, protocols like ARQ & FEC, or why network acceleration techniques used for office traffic do not work for video. (everyone sleeping now?)
 

jlinder

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Re: Streaming Video-How it works?

The article claims that Netflix is throttling back the writers data rate for movies. The reality is that a number of ISPs have been caught doing this for one reason or another.

For example, Comcast has said they will slow down or limit access to certain sites if it wants to do so. The FCC took them to court but lost on appeal on this. (Google net neutrality comcast)
 
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