Montag, 29. Juli 2013

The Realworld : LIVE broadcasting with the 5D Mark III

So, i spent the biggest part of my last week on getting actually a real live-broadcasting session going with a 5D Mark III. I don't talk about a Live-Session for some sorry ass online stream that no body watches, but actually a live quality that can be used by REAL broadcast media ( like TV Stations i.e. ).

I have to admit, i haven't really been completely successful. But I will guide people here through my steps and the caveats i had to work around etc.

First of all, get the latest Firmware update for the 5D Mark III. On the day this was written we are still on the 1.2.1. That gives us clean, uncompressed HDMI output. For streaming via internet from some ass-of-the-world-place I have to admit i could care less about the resolution ( cause we have to compress our signal again a lot to actually get it to places via a BGAN or something ) but we get a CLEAN signal. Means, we dont have all this letterboxes, menu's etc.

I would have loved if the 5D would have an SD outgoing CLEAN signal, but that is not what the camera is meant for and i clearly try to push the boundaries here, so no complaint.

On top of that we need to tell the camera how we want our HDMI signal to be processed. We can do that in the camera Menu. There is an item that let us define what settings the HDMI should use. We have the choice between the 24p and the 60i. Working ona  progressive plattform I choose the 24p for now ( which is actuall of course more like the 23.98p ).

To pipe in our nice, CLEAR and uncompressed HDMI signal to my MacBook Pro (MBP) ( iCore7i, 2.2 Ghz, 8GB Ram ) I took a Blackmagic Intensity Shuttle with Thunderbolt connection.
To stream my media i tried Telestream Wirecast and Livestream ProCaster.

After connecting the cam via HDMI cable to the Intensity Shuttle, and the Shuttle to the MBP via Thunderbolt I start up the included Blackmagic Media Express tool that comes with the Shuttle. Before doing the whole Shebang, I just want to check if I get a general signal from the camera.

After starting up, the screen stays black. So obviously no signal. Withs some research i find out that I have to look out for 2(!!) settings. One is in the Blackmagic driver software, which we can access through the "Settings" menu in OSX the other is in the Blackmagic Media Express. In both menus we have to specify the HDMI signal. Which is of course 23.98 p.
After doing that the screen shows the nice, clean output from the 5D Mark III.

The first thing we have to understand is, that the HDMI out of the 5D Mark III doesn't deliver any sound. Its only the video signal. The Shuttle has next to the HDMI input also a phono-stereo connection ( the white and red plugs we all love from our home-stereo-systems ). Or there is the alternative, to connect the microphone directly to the MBP Line-In.

Not having a Jack-Phono cable at hand first, i just connected the microphone to my Line-In. That at least gave us some audio signal. But the audio signal is heavily delayed.
In general piping out a uncompressed HDMI signal to a computer like mine, puts a lot of pressure on the ressources. I haven't really figured out by now if its my computer or the Intensity Shuttle, but the video in general is slightly delayed for a few frames.
The sound is even worse.

After doing some more research, it turns out that there are many sound issues. Many people seem to have the problem that the sound comes first and the visual lags behind. That comes mainly from the fact, that the video signal has to be dealt with and it takes some time to calculate the operational encoding etc. with such a data heavy HDMI signal.

But in my case, the SOUND actually comes late. It seems that the apple OS is first processing the Thunderbolt signal and then it connects the Line-In. This could be due to calculation limitations on my computer or just a design-"flaw" ( internal technical limitation ). I could not figure that out, for me here in Kenya not having a "newer" MBP with more calc power or more memory.

The only solution I could think of, is to take the sound out of the 5D Mark III and to connect a 3.5 jack to phono cable to the Intensity Shuttle. In that way i hoped that the sound and the video gets mixed into one signal that actually is itself synced to each other...even maybe in its entire form delayd...

But after doing all doesn't. Sound is still significantly delayed in Telestream Wirecast preview. Actually so much, that it is virtually unusable.

BUT: After recording in some testfile...i realized...its actually pretty much in sync. And that is awesome.

The biggest problem still is the amount of data. We have quite big data chunks that need to be converted to a lower res signal ( for online transmission ) and that can actually eat up quite some processing power. Maybe it could be even too much for my little machine, which would end up in quite a delay on the receiving end.

Using Telestream Wirecast i was testing it with UStream to some other computer and the lag was just enormous. But this could originate from quite some different issues...internet speed on the othe side, my own internet speed, encoding/decoding on the receiving end etc.

My assesment so far: online Live broadcasts via DSLR's can work, if the internet speed is fast enough, the computer is a powerful machine that can decode/encode the HDMI signal in a good timeframe and the receiving end of the broadcast isn't a bottle neck either. So, many "IF's" in the end.

UPDATE: based on the BM documentation of the Desktop Video drivers for the whole Intensity series etc. the driver settings ( which, remember, you access via the OSX Settings window ) as apparently the functionality to convert the high res HDMI signal to something more usable for Live-Streaming. Unfortunately, it doesn't really seem to work. Absolutely independent on what I click on the drop down menu on the OSX version of the drivers, its all the same in the end ( on top of it all, the manual screenshot looke like nothing as I get with the 9.7.5 drivers on my mac ):

UPDATE: Looks like there is no real-time down conversion in the Intensity Shuttle during capture. Only during playback by software. That means, you can't let the Shuttle do the dirty work for you and most likely you need a REALLY FAST machine.

Just also for info, here are the specs of the computer i used for this test:

MacBook Pro , model late 2011
iCore7i 2.2 Ghz
8 GB Ram
AMD Radeon HD 6750 M

Keine Kommentare:

Kommentar veröffentlichen