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re: broadcasting “in hd”
hello…
i trust you’ll correct me if i’m wrong, but merely connecting to wirestream with an HDV signal, or using the HD-SDI input of a black magic card, does not mean you are “broadcasting in hd”
yes, you are sending an hd signal to the computer.
however. the encoding you select will still be flash, or quicktime, or something of the like, and unless you are encoding at 1280×720, or 1920×1080, you are “broadcasting” in “sd” (or something even smaller, resolution-wise, like 320×240, in some cases).
your encoder card may ACCEPT an hd signal, but encodes to a web-delivery-friendly codec so that users can view it, the larger ones being in the 640×480 neighborhood, if 4:3.
we do some live broadcasts with both wirecast and adobe flash encoder… when using wirecast we take an SD sdi signal, even though we have HD-SDI inputs are available.
i believe that sending in an hd signal makes the encoder work harder, which makes performance suffer, to bridge the gap from the huge HD signal coming in to the smaller signal streaming out.
of course, that’s a superficial belief, i don’t have the sophistication to test it…
but the superficial reasoning continues that if you send in a 720×486 signal (standard def, sdi, component, whatever) the encoder will not have to work as hard, in order to produce the same 640×480 flash stream on the other end.… right?
-jesse
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6 Replies
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1280×720 at 1500kbps = HD.
You would NOT want to send HD to the computer to broadcast in SD. You’re asking the computer to use a lot of CPU to downrez, decode, encode. If doing SD broadcast you want to downrez BEFORE the signal hits the computer.
HD streaming is very possible at 720 and people using Watershed and Livestream Pro are doing it (amongst others).
Granted not everyone can view 1500kbps but certainly someone with a cable modem or very fast DSL can. By comparison YouTube HD progressive download is about 2000kbps and Vimeo is around 1600kbps last I checked so the quality at 720 at 1500kbps is OK.
BTW HDV as you might guess is a real challenge to decode and encode live to 720 at 1500kbps but it can be done if you’re only using 1 camera. I’ve done it on my MacPro.
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Thanks Craig, Jesse and I have been arguing about this since I talked to you earlier and I guess I win. What do I win, Jesse?
Scot Lenter
Midtown Video
Miami, Florida
Service Manager
Rental Agent
scot@midtownvideo.com
305-669-1117 -
you win the chance to try to watch a live stream at 1500kbps
best of luck bro.
the important thing to take away from this, is that connecting to your computer with a high definition signal ~as of today~ is counter-productive, as i posted earlier, because you want to give an SD signal for your SD stream so as not to overwork your encoder.
when the internet can deliver a reliable 1500kbps signal to enough viewers at once to make an hd webcast viable, you can worry about connecting an HD signal to your encoder.
refer to craig’s mention of both youtube and vimeo. do either of those “stream” nicely to your workstation, or do you have to leave it on pause while the video loads up, slower than real time?
imho, we are not there yet. so, set your phasers to ‘downconvert’ and impress your friends with high quality video not much larger than 640×480, 25~30 fps. progressive would help also, i believe.
check out https://www.jtown.tv for impressive live broadcasts in just such a format. next broadcast, October 15th, 6:30pm, working title: “how to broadcast live video to the internet, with jesse miller”
youtube should be filling up shortly with highlights from last thursdays show, “tips and tricks on the ex3, with jesse miller”
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[jesse miller] “when the internet can deliver a reliable 1500kbps signal to enough viewers at once to make an hd webcast viable, you can worry about connecting an HD signal to your encoder. “
Depends on your market. In my area Cable Modem generally starts at 15,000kbps and goes up to 101,000kbps.
DSL is 1000kbps, 3000kbps, 7100kbps.
That would mean all be the base tier DSL is at least double 1500kbps.
[jesse miller] “refer to craig’s mention of both youtube and vimeo. do either of those “stream” nicely to your workstation, or do you have to leave it on pause while the video loads up, slower than real time? “
I have 30,000kbps and they play smooth as silk in HD at 1280x720p.
Obviously this is not the case in all markets but if you’re targeted a market or “class” of viewers that have high speed (and I’m talking consumer service) service then HD will work for that market.
BTW I think Hulu hits that data rate with their HD selections (which are very few) as well.
I’m pretty sure Netflix is over 1000kbps at their highest quality too. -
Something to keep in mind is MAKE SURE you par is th same before and after transcode. This will ase up the processor performance. In Dallas, th best speed on dsl I could find for residential is like 6 MBpS up and 750Kbps down. Hardly worth sending an hd signal.
Jeff
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[Jeff Mack] “In Dallas, th best speed on dsl I could find for residential is like 6 MBpS up and 750Kbps down. Hardly worth sending an hd signal. “
It sounds like you have those numbers reversed. 6mbps sounds like down and 750kbps up.
Don’t confuse sending with viewing. 6mbps is absolutely great for viewing a 1500kbps 720p stream.
Sure the 750kbps upstream isn’t enough but only the streamer needs to have the upstream bandwidth. Viewers need only worry about down bandwidth.I have 5000kbps up and it wouldn’t even cost much more to get 15,000kbps up in my area. 101mbps down 15mbps up is $99 month. 5000kbps is plenty though and 30,000kbps down 5000kbps up is about $55 month.
At 5000kbps up I can stream 1280×720 HD and my MacPro 8 core handles that EASILY. Basically anyone with 3000kbps down and faster DSL or CableModem should have no problem with that.
Hulu, YouTube, Netflix all use 1500kbps – 2200kbps for viewing their highest quality content. All are mainstream services. They offer it because the market is large to enough at those bandwidths.
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