javascript - Bypass the 6 downloads limit for multiple videos watching - Stack Overflow

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I have to code a website with the capability of watching many live streams (video-surveillance cameras) at the same time.

So far, I'm using MJPEG and JS to play my live videos and it is working well ... be only up to 6 streams !

Indeed, I'm stuck with the 6 parallel downloads limit most browser have (link).

Does someone know how to by-pass this limit ? Is there a tip ?

So far, my options are:

• increase the limit (only possible on Firefox) but I don't like messing with my users browser settings

• merge the streams in one big stream/video on the server side, so that I can have one download at the time. But then I won't be able to deal with each stream individually, won't I ?

• Switch to JPEG stream and deal with a queue of images to be refreshed on the front side (but if I have say 15 streams, I'm afraid I will collapse my client browser on the requests (15x25images/s)

Do I have any other options ? Is there a tip or a lib, for example could I merge my stream in one big pipe (so 1 download at the time) but have access to each one individually in the front code ?

I'm sure I'm on the right stack-exchange site to ask this, if I'm not please tell me ;-)

I have to code a website with the capability of watching many live streams (video-surveillance cameras) at the same time.

So far, I'm using MJPEG and JS to play my live videos and it is working well ... be only up to 6 streams !

Indeed, I'm stuck with the 6 parallel downloads limit most browser have (link).

Does someone know how to by-pass this limit ? Is there a tip ?

So far, my options are:

• increase the limit (only possible on Firefox) but I don't like messing with my users browser settings

• merge the streams in one big stream/video on the server side, so that I can have one download at the time. But then I won't be able to deal with each stream individually, won't I ?

• Switch to JPEG stream and deal with a queue of images to be refreshed on the front side (but if I have say 15 streams, I'm afraid I will collapse my client browser on the requests (15x25images/s)

Do I have any other options ? Is there a tip or a lib, for example could I merge my stream in one big pipe (so 1 download at the time) but have access to each one individually in the front code ?

I'm sure I'm on the right stack-exchange site to ask this, if I'm not please tell me ;-)

• javascript
• web
• streaming
• mjpeg

Share Improve this question Follow asked Mar 25, 2020 at 9:02 Julien GreardJulien Greard 1,04911 gold badge1414 silver badges3434 bronze badges

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2 Answers 2

Sorted by: Reset to default 3

Why not stream (if you have control over the server side and the line is capable) in one connection? You do one request for all 15 streams to be send /streamed in one connection (not one big stream) so the headers of each chunk have to match the appropriate stream-id.
Read more: http://qnimate./what-is-multiplexing-in-http2/
More in-depth here: https://hpbn.co/http2/
With http1.0/1.1 you are out of luck for this scenario - back then when developed one video or mp3 file was already heavy stuff (work arounds where e.g. torrent libraries but unreliable and not suited for most scenarios apart from mere downloading/streaming). For your interactive scenario http2 is the way to go imho.

As Codebreaker007 said, I would prefer HTTP2 stream multiplexing too. It is specifically designed to get around the very problem of too many concurrent connections.

However, if you are stuck with HTTP1.x I don't think you're pletely out of luck. It is possible to merge the streams in a way so that the clientside can destructure and manipulate the individual streams, although admittedly it takes a bit more work, and you might have to resort to clientside polling.

The idea is simple - define a really simple data structure:

---

[streamCount len1 data1 len2 data2 ...]

Byte 0 ~ 3: 32-bit unsigned int number of merged streams

Byte 4 ~ 7: 32-bit unsigned int length of data of stream 1

Byte 8 ~ 8+len1: binary data of stream 1

Byte 8+len1+1 ~ 8+len1+4: length of data of stream 2

...

Each data is allowed to have a length of 0, and is handled no differently in this case.

---

On the clientside, poll continuously for more data, expecting this data structure. Then destructure it and pipe the data to the individual streams' buffer. Then you can still manipulate the ponent streams individually.

On the serverside, cache the data from individual ponent streams in memory. Then in each response empty the cache, pose this data structure and send.

---

But again, this is very much a plaster solution. I would remend using HTTP2 stream as well, but this would be a reasonable fallback.

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