If your Castr stream has audio but a black picture, set the encoder’s video codec to H.264 (AVC) and its keyframe interval to 2 seconds. If the Castr preview shows video but YouTube does not, check that the encoder is sending both audio and video tracks. For an uploaded video, confirm it is an MP4, then inspect the incoming preview and stream statistics to find where the picture disappears.
Find where the video disappears
Use Castr’s incoming-source preview and live statistics before changing settings. The preview shows the source coming into Castr; the dashboard can show bandwidth, viewers, bitrate, resolution, codecs, and audio bitrate. These checks can help narrow down the fault, though the preview is not guaranteed to identify every problem. See Castr’s live-stream monitoring workflow.
- The Castr preview is black: investigate the encoder’s video output or the source file first.
- The Castr preview shows video, but YouTube is black: check the destination output and verify that the encoder sends both audio and video tracks. Castr notes that some platforms reject streams without both.
- The preview and destination both show video: the fault may be farther downstream or intermittent; use the live statistics to check whether video bitrate, resolution, and codecs are present rather than assuming a single setting is responsible.
Fix a black picture when audio is present
Castr’s March 18, 2026 troubleshooting guidance links a black screen with audio to an incompatible video format. Change the encoder’s video codec to H.264 (AVC) and set the keyframe interval to 2 seconds. These are Castr’s symptom-specific recommendations; changing bitrate alone is not its stated fix for this symptom. Read Castr’s stream-quality troubleshooting guidance.
Check that both tracks are being sent
If YouTube receives audio but no picture while the Castr preview shows video, inspect the encoder’s output configuration and confirm that it is sending a video track as well as audio. An audio-only signal cannot produce a picture at the destination.
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Check an uploaded video file
Castr’s video upload guide says the service supports MP4 files only. If the source is an uploaded recording, check its container and use an MP4 file. The guide does not specify a complete transcoding recipe or guarantee that every MP4’s internal video format will work; if the file is accepted but the preview remains black, check video compatibility, including H.264, rather than relying on the .mp4 extension alone.
Upload-size considerations
The same guide says direct local upload is recommended for files under 5 GB and that direct upload is not resumable. It describes multipart upload for files above 5 GB as “coming soon.” Those are upload-process details, not established causes of a black picture.
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Use bitrate and resolution guidance as supporting checks
After checking codec, keyframes, and tracks, review the remaining encoder settings if the stream also stutters, drops, or has unstable quality. Castr’s two configuration pages give somewhat different 1080p bitrate ranges, so use each in its own context rather than blending them into a single guaranteed setting.
| Setting | Castr troubleshooting page (March 18, 2026) | Castr encoder configuration guide |
|---|---|---|
| Video codec | H.264 (AVC) | H.264 |
| Bitrate mode | CBR | CBR |
| Keyframe interval | 2 seconds | 2 seconds; not over 4 seconds |
| 1080p at 60 fps | 3,500–6,500 Kbps for 1080p generally; the page does not give a separate 60 fps range | 4,500–9,000 Kbps |
| 1080p at 30 fps | 3,500–6,500 Kbps for 1080p generally | 3,000–6,000 Kbps |
| 720p at 60 fps | 2,500–4,000 Kbps for 720p generally; the page does not give a separate 60 fps range | 2,250–6,000 Kbps |
| 720p at 30 fps | 2,500–4,000 Kbps for 720p generally | 1,500–4,000 Kbps |
| Resolution and frame rate | 1920Ă—1080 or 1280Ă—720; 30 fps, or 60 fps if the connection supports the higher bitrate | Bitrate ranges listed for 1080p and 720p at 30 and 60 fps |
| Audio | AAC, 128 Kbps stereo | AAC or MP3; 128 Kbps preferred and not above 256 Kbps |
These are general streaming recommendations, not a promise that a bitrate change will fix a codec-related black screen. The troubleshooting page’s 1080p range differs from the encoder guide’s separate 1080p-at-30-fps and 1080p-at-60-fps ranges. See the Castr encoder configuration guide for its resolution- and frame-rate-specific values.
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Troubleshoot by symptom
| What you see | What to check next |
|---|---|
| Audio and black picture in Castr preview | Set encoder video to H.264 (AVC) and keyframes to 2 seconds; for a file source, confirm MP4 and investigate its video compatibility. |
| Video in Castr preview, audio only on YouTube | Confirm the outgoing encoder signal includes both video and audio tracks; inspect the destination output. |
| Black picture from an uploaded source | Confirm MP4, then check the video codec; an MP4 extension alone does not establish internal codec compatibility. |
| Video present but stream quality is unstable | Use Castr’s bitrate, resolution, codec, and audio statistics to assess the signal; consider CBR and the relevant resolution/frame-rate range above. |
| Settings and signal appear correct, but the fault persists | Check Castr’s status page. Its listed update at October 2, 2026, 4:26 pm UTC showed all services online; that is a timestamped snapshot, not evidence of service state during a later incident. |
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Quick Recap
Best Value
- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
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