Follow this guide to have the best settings for recorded videos before uploading to Castr's pre-recorded streams. If your video is not formatted to our suggested configuration, the stream might be stopped during the live broadcast due to the video's settings.
For more details on how to get started with scheduled streams, please read this tutorial.
Castr Scheduler currently only accept mp4 video files for pre-recorded stream. Here are the full settings for recording videos:
Video Format: MP4
Rate Control: Constant Bitrate (CBR)
Keyframe Interval: 2 Seconds
Recommended Resolution: Full HD (1920x1080)
Recommended Frame Rate: 30 FPS
Recommended Bitrate: 4,000 Kbps (4.0 Mbps)
*Important note: Castr highly recommends that when recording the video, you should include an additional 10-20 seconds at the beginning and the end of your stream.
A quick tip to do this is to add a "Stream starting in a few seconds" message before going live and an end message at the end of your stream. This is to avoid missing a few seconds of your recording when it is processed by our CDN and goes live on the end platform.
How to lower bitrate for videos and recordings
There are cases where the pre-recorded streams could not reach certain platforms, and the cause of the issue is usually the video's too high bitrate.
To avoid this, you can use an application called HandBrake to lower the bitrate and FPS on your videos/recordings.
Download HandBrake from its website. The app is available for Mac, Linux, and Windows.
After finishing the installation, open your video in Handbrake
In the Summary tab:
Select Preset as Fast 720p30. Feel free to choose otherwise, but this is a decent output.
4. In the Video tab
Video Codec should be set to H.264 (x264).
Select Framerate (FPS) as 30 and choose Constant Framerate.
Select Quality as Average Bitrate (kbps) with 2-pass encoding enabled. We recommend an average bitrate between 1500 kbps to 2500 kbps to accommodate different platforms.
The above should be enough for your normal video, but if your video fluctuates a lot in bitrate, it's recommended to add the below line to Advanced Options:
The option in Advanced Options is separated by a colon.
You can find a deep explanation for each option here.
We recommend that you set vbv-maxrate = 1.25-1.5x of the average bitrate. Example: Average bitrate = 2500 kbps, then your vbv-maxrate is about 3500 kbps.
vbv-bufsize should be doubled by the vbv-maxrate value. Example: your vbv-maxrate is 3500, then your vbv-bufsize should be 7000.
keyint is the number of pictures within the current GOP (aka “keyframe interval”). It should be doubled the framerate number. In our setting, the framerate = 30, so the keyint = 60.
5. In the Audio tab
On the first track, select Codec as AAC (avcodec).
Select a Bitrate between 128 and 320 Kbps. We recommend 128 Kbps if you plan to stream to Facebook and Youtube.
Ensure there is only 1 track. If there are multiple tracks of audio, remove the other tracks and leave one 1 track.
6. Click Start Encode, wait for the encoding process to finish then upload your encoded video to Castr.
Please reach out to our 24/7 support if you have more questions.