Open Broadcaster

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Open Broadcaster (OBS) is open source video encoding and streaming software. Note: This guide is for the newer multiplatform version. The instructions may apply to the original version, but will deviate slightly.

Configuration

Audio

The following settings under the audio tab want to be changed:

Sample Rate: 48khz
Channels: Stereo
Desktop audio device: Disabled
Mix/Auxilary audio device: Disabled

The rest of the dropdowns should also be disabled.

Audio is read from the blackmagic card in a seperate location.

Video

The following settings under the video tab want to be changed

Renderer: Direct3D 11 (unknown what other options will do)
Base (Canvas) Resolution: The output resolution
Output (Scaled) Resolution: Same as above
FPS: 25

The FPS may want to be different if using a source that is not 25p or 50i. A general rule is that it should either match or halve the framerate for a progressive source, and be half the field rate for an interlaced source.

Video Quality Presets

Under output settings, select Output Mode: advanced, simple does not provide enough control.

If internet bandwidth is limited, the video bitrate can be lowered within limits.

Any settings not specified below should be left as default, but could have either positive or negative effects and are untested as to their effects. Eg. using the Quicksync encoder will massively reduce cpu usage, but has previously caused issues with audio sync.

YouTube HD

Streaming:

Audio Track: 1
Encoder: x264
Rescale Output: No
Bitrate: 6000
Keyframe Interval: 2
Use CBR: Yes

YouTube SD

Streaming:

Audio Track: 1
Encoder: x264
Rescale Output: No
Bitrate: 4000
Keyframe Interval: 2
Use CBR: Yes

Guild Council SD

Streaming:

Audio Track: 1
Encoder: x264
Rescale Output: No
Bitrate: 2500
Keyframe Interval: 2
Use CBR: Yes

Local Recording HD

Streaming:

Audio Track: 1
Encoder: x264
Rescale Output: No
Bitrate: 100000
Keyframe Interval: 2
Use CBR: Yes

Recording:

Type: Standard
Recording Path: Should be set to the recording hard drive
Recording Format: flv
Audio Track: 1
Encoder: (Use Stream Encoder)

Note: this will use 600mb of hard drive space a minute, and will require a decent hard drive to be able to cope. The Record HDD in Gretchen was bought for this purpose and can handle recording a couple of streams simultaneously.

Local Recording SD

Streaming:

Audio Track: 1
Encoder: x264
Rescale Output: No
Bitrate: 30000
Keyframe Interval: 2
Use CBR: Yes

Recording:

Type: Standard
Recording Path: Should be set to the recording hard drive
Recording Format: flv
Audio Track: 1
Encoder: (Use Stream Encoder)

Note: this will use 180mb of hard drive space a minute, and will require a reasonable hard drive to be able to cope. The Record HDD in Gretchen was bought for this purpose and can handle recording a couple of streams simultaneously.

Stream RTMP Settings

YouTube

To configure for YouTube, you will need to first setup youtube to expect a stream of the desired resolution, and retrieve the stream url and id to be used. This should be in the format of:

Stream Name: yt-ems-t.-NQTM-6crwY3loNo5vbt9g1364075191866365.121
Primary Server URL: rtmp://a.rtmp.youtube.com/live2?sparams=id%2Citag%2Cns%2Cexpire&expire=1445711526&ns=yt-ems-t&signature=C0634E0104C5C2C58A9CD541CAD9537339619BA8.5E6F7120B95AD43BA1BC1725BC90FB3B840B471F&id=-NQTM-6crwY3loNo5vbt9g1364075191866365&key=yt_qc&itag=121

This translates to OBS very simply:

Stream Key: Stream Name
URL: Primary Server URL

Other

For a custom streaming server, such as the nasta service, you will typically have a url such as:

rtmp://192.192.18.15/live/GTV

This translates to OBS as follows:

Stream Key: GTV
URL: rtmp://192.192.18.15/live

Setting the scene

Adding a Blackmagic source

File:OBS-scenes-sources.png

There should already be a scene in the scene selector, if not then one should be created.

If there is already a Blackmagic capture in the sources selector then you can double click on that to open the configuration, otherwise click the plus to add one.

The Blackmagic source requires only configuration to select the mode that it should operate under, and also to select which card to use (in case there are multiple in the system). Once the correct mode is selected, input signal should be visible in the dialog.

File:OBS-blackmagic-signal.png

Once this has been done the dialog can be closed, and the source can be scaled and cropped in the next step.

Scaling or cropping a source

Once the source has been added it may look something like the following where it does not correctly fill the space.

File:OBS-prescale.png

The first step to solve this, is to right click the element, and select Transform;Stretch to screen. Be careful as this can skew the aspect ratio if something is configured incorrectly.

If working with the PD150s, or other analogue cameras, it is likely that there will be a black border around the video still. This is from the output of the cameras, and can be solved by simply scaling the video further to trim the offending bits off screen.

To do so, click and drag on the red circles on the edges of the video source until the black bars are not visible any more. It is worth checking after this step on different cameras to ensure the bars are gone for all of them.

Notes

Recording

FLVs are not the easiest to work with when editing, especially when the files are many hours long. It is advised to record in them though as they handle crashes a lot better than MP4s do. If the software or machine recording in FLV crashes, then only a recent portion of the video should be lost, however an MP4 in the same scenario will likely become corrupt beyond repair.

It is easy to convert an flv to mp4 without losing quality after the recording has been made, so mp4s can be produced afterwards if needed

External links

Project home