I am a bit confused about what is slowing down my network and I hope it is correct to ask here and not at "webapps.sx.com", because my issue is not only one with YouTube, but basically many video sites.

I cannot understand how I, living in Seoul (South Korea), sporting a 100 Mbit LAN connection, have problems with content buffering and streaming? What I noticed is, when I use a advanced Download-Manager like jDownloader or DownThemAll or even a standard download manager, an e.g. YouTube video downloads pretty quickly - and I always download them in 720p.

But when I try to stream the same video - embedded on a site or directly on YT - it does buffer forever and loses all their progress (wtf??) when I go from the "small preview" to fullscreen mode! And all that is usually in 360 or 480p, not 720p! (I never watch in 720p because it is absolutely impossible.) Vimeo is a bit better, the only video site I noticed performs better. I had the same issue already back in Germany with a 30-33 Mbit LAN connection. This is especially confusing as the download speed for a YT video normally reaches 2-2,5 MB/second in "jDownloader" (otherwise I didn't measure), so that should be enough when it'd buffer with the same speed. Why is this not the case, is there a technical reason?

Why can't even Google / YouTube - seemingly - provide a fast enough buffering / streaming experience, what is the problem? Is it my PC / hardware? My laptop sports a Intel DualCore i7 (2010 generation) with 6 GB of RAM and always use the most recent Google Chrome browser and Adobe Flash Update.

Attached you find a most recent speedtest.net result: speedtest.net result.

What is going on there?

  • I have edited my answer, please have a look at it again.
    – Michael K
    Feb 3 '12 at 10:12
  • 2
    77Mb/s?? I'd kill people for that kind of bandwidth at my home.
    – surfasb
    Feb 3 '12 at 12:13
  • As we all know we have to divide by eight, so we get a nice pure 9,655 MB/s Down- and Upload speed. But (at least according to jDownloader) I already managed to achieve over 10 MB/s via several OCH connections, as obviously the maximum capacity here is more in the ninety's (90 Mb/s)... Feb 3 '12 at 16:02

You may also want to consider your location; East Asia - even though South Korea is very well connected internally and within the region, its links externally to the west are much poorer and typically are very overloaded (Recent boom is computer ownership and speed of residential connections is not matched with the backbone capability).

Additionally, while Google does have data centers in the region; the cost of hosting when compared to the west is still significantly higher (they will be getting charged arms and legs for bandwidth) meaning the local capability might not meet the demand, leading to other bottlenecks (or you may be load balanced to a more western server, bringing us back to point 1). Note that this is speculative as Google do not release figure on their infrastructure, and quite often hide the fact that certain locations even exist.

  • That is a good point! But then why is "DownThemAll", jDownloader or any other download manager (even the built-in one) able to download the video from a link much faster than it can buffer the SAME video? I guess I basically need to do some research on buffering, to me there seems to be the key issue. Feb 3 '12 at 10:05
  • Download managers usually work by starting multiple concurrent download threads from the same link, starting at different locations in the file (via HTTP Chunking). As a result they will tend to show a performance nearer to the maximum capability of your connection than would be possible over a single connection due to a variety of factors ranging from per connection throttling on servers to the configuration of how TCP packets are handled on your machine/router/ISP/etc.
    – Turix
    Feb 3 '12 at 10:13
  • Also as a side note; there may also be some behind the scenes traffic management in play somewhere between you and Google, depending on the exact technical implementation of the Youtube player (if it uses something like RTSP rather than HTTP to stream the media). ISPs tend to dislike video streaming because of the massive amounts of traffic they generate on the networks and some more malicious ISPs target it for management.
    – Turix
    Feb 3 '12 at 10:24
  • Dear Turix, so you say an ISP is able to recognize I am playing a YouTube video, but if I am downloading the same YT video, this ISP is not able to recognize that or will not penalize me? Why should an ISP penalize me, when I have 77 Mbit/s available here both down and up? And/or: Why are Google/YT and others not using the same "HTTP Chunking" for their buffering? (Might sound stupid to you, but I just see it from the "results"/"customer experience" perspective.) Feb 3 '12 at 15:49
  • My q. still stands: Why can't video services not perform at a rate that is: Not equal to a DL manager speed BUT at least loading the content as fast as it is naturally playing? I mean no one wants preloading and I'm ok with it taking a while when I skip over video parts, but why does the buffering tend to lag behind the actual play speed, which is one second at a time? There must be way to calculate: e.g. 480p = xy KB usage * 30 frames/sec = Necessary KB (or MB) that need to be buffered p.s.? PS: I found this: broadbandforum.in/india-broadband/… Feb 3 '12 at 15:52

This problem is caused due the fact that 100mbit is the speed of you local home network, (LAN = Local Area Network) and not of your internet connection Judging from your download rates 2-2,5mb/s, you seem to have ~20mbit internet connection. Also, you do not know how broad the connection to sites like youtube really is.

No, it has nothing to do with your hardware, if your car runs out of gas, you do not blame the engine for that, right?


The cause of the buffering problem is, when you change to fullscreen mode, usually the player automatically detects the larger screen size and tries to load the video in a more suitable resolution. Of course, the whole previously buffered progress is worthless at this point. I suggest you to start buffering, then go directly to fullscreen mode and switch back to normal, most players will load the higher resolution after this and won't go back to the lower resolution video.

If you still face buffering problems after trying this, you should contact the individual hoster for further service. You may also check the connection bandwith for each individual connection to make sure that there is no connection issue with the host.

Addition 2

Since your bandwidth seems to be more then enough for streaming, please note that your bandwidth is not the streamhosters bandwidth. In your case, the buffering speed depends on the hosts bandwidth and most video hosts are heavily occupied (and giving premium users higher priority, if there are premium users), so this problem cannot be fixed by yourself.

  • -1. author explicitly stated that video downloads just fine outside of the flash player, but 360p lags badly in flash player. I have the same problem and I'm looking forward to hear answers Feb 3 '12 at 9:44
  • The author asked more than one question, but you are right, I'll try to answer this issue, too.
    – Michael K
    Feb 3 '12 at 10:00
  • Dear Michael K., I am not stupid, even though I failed to provide all the details at once: My local LAN connection from a hardware side is actually 1000 MBit (i.e. GBit). But I know that this does not matter. You can see my connection now above, it is 77 Mb/s, which is (says speedtest) faster than 92% of the country. And fyi please read this: en.wikipedia.org/wiki/Internet_in_South_Korea Feb 3 '12 at 10:02
  • 2
    "...sporting a 100 Mbit LAN connection..." - the why did you call it LAN? LAN != Internet Connection
    – Michael K
    Feb 3 '12 at 10:07
  • Maybe I should've called it internet connection. My bad. But I pointed it out to avoid calling me out on if I use Wifi! (I'm sure it would've happened...) After all it runs over LAN vs. (compare) WLAN/Wifi, 3G, 4G/LTE (also available here!), tethering and other techniques! Feb 3 '12 at 15:44

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