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For a 4K 60fps YouTube Live stream, set the keyframe interval to 2 seconds. If your encoder asks for GOP length in frames at exactly 60fps, use 120 frames (60 × 2). YouTube says not to exceed 4 seconds—equivalent to 240 frames at 60fps—and recommends a closed GOP. These are platform-level settings; the exact controls depend on your encoder and ingest protocol.
Recommended 4K60 GOP and keyframe settings
| Setting | Recommended value | What to check |
|---|---|---|
| Resolution and frame rate | 3840 × 2160 at 60fps | Use this only if both your source and encoder can produce it. |
| Keyframe interval | 2 seconds | YouTube’s recommended frequency for RTMP/RTMPS; do not exceed 4 seconds. |
| GOP length at exactly 60fps | 120 frames | Calculated from 60 frames per second × 2 seconds. The 4-second maximum corresponds to 240 frames. |
| GOP type | Closed GOP | Do not use open GOP. YouTube’s API flags it as unsupported, and the HLS guide requires closed GOP. |
YouTube publishes the interval as a time value, not as a frame-count setting for every encoder. Prefer the time-based control if your encoder offers one. If you use a frame count, confirm the actual frame rate and verify the resulting interval in YouTube stream health. A non-integer or variable frame-rate workflow may not map cleanly to a fixed frame count.
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Set bitrate and the other encoder parameters
Choose a bitrate for the ingest codec
| Video codec | 4K/2160p at 60fps minimum | Recommended bitrate |
|---|---|---|
| H.264 | 14 Mbps | 50 Mbps |
| AV1 or H.265/HEVC | 10 Mbps | 35 Mbps |
These are YouTube’s listed bitrate values for the specified resolution, frame rate, and codec—not a guarantee that your encoder or upload connection can sustain them. Choose a rate your equipment and connection can maintain reliably, and test before the event. YouTube transcodes live streams into different output formats for viewers. Its guidance says 4K streams use normal latency; low-latency mode is unavailable for 4K.
RTMP/RTMPS settings
YouTube’s general encoder-settings table applies to RTMP/RTMPS. It recommends RTMPS and lists H.264, H.265/HEVC, and AV1. For this ingest route, use:
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- CBR bitrate encoding.
- Progressive scan and square pixels.
- Two B-frames and one reference frame.
- CABAC.
- For SDR, Rec. 709 and 8-bit are recommended.
- For HDR, YouTube recommends H.265/HEVC and 10-bit; AV1 is not supported for HDR. At 3840 × 2160 and above, AV1 streams need at least two tile columns.
Codec choice does not change the recommended two-second keyframe interval. Check that your encoder and chosen ingestion route support the codec and any HDR format you need.
Do not mix up RTMP and HLS requirements
YouTube documents RTMP/RTMPS and HLS as distinct ingest types. The HLS guide is specifically for HLS: it requires muxed M2TS audio and video, H.264 or HEVC video, and a single AAC audio track. It supports frame rates up to 60fps, requires closed GOP, recommends media segments of one to four seconds, and caps segment length at five seconds. Those M2TS, AAC, and segment rules are not RTMP/RTMPS settings.
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Configure and verify the stream
- Match the output to the source. Set 3840 × 2160 and 60fps only if the recorded video and encoder support those output settings. Choose the ingest codec and bitrate from the table above.
- Set the keyframe interval. Enter 2 seconds. If the encoder only accepts GOP frames and the stream is exactly 60fps, enter 120 frames. Do not exceed a 4-second interval (240 frames at 60fps).
- Select a closed GOP. Disable open GOP if the encoder exposes that option. If you are using HLS, closed GOP is an explicit requirement.
- Check the remaining encoder settings. For RTMP/RTMPS, confirm CBR, progressive scan, square pixels, two B-frames, and one reference frame. Apply the relevant SDR or HDR recommendations without mixing the two.
- Test with representative content. Before the event, test using audio and motion similar to the intended stream. For a video loop, include the transition at the loop point as part of the preflight; this is a practical test, not a separate YouTube loop-specific requirement.
- Monitor YouTube stream health. Review health messages during the stream and compare any reported GOP problem with the encoder’s output and the stream’s behavior.
YouTube’s Live Streaming API includes diagnostics for long GOPs, open GOP, and mismatched GOP settings between primary and backup streams. Use the same keyframe frequency for both primary and backup streams. YouTube also warns that ingest errors can make GOP-size readings incorrect, so treat a diagnostic as a clue to investigate rather than the only measurement.
Troubleshoot GOP and keyframe warnings
| Symptom or API issue | Likely cause | What to check or change |
|---|---|---|
gopSizeLong or gopSizeOver |
Keyframes are too far apart, or an ingest error has affected the diagnostic. | Set the interval to 2 seconds and keep it at or below 4 seconds. Verify the encoder’s actual output and review other stream-health messages. |
openGop |
The encoder is producing open GOP. | Change the encoder to closed GOP. YouTube’s API says open GOP is unsupported. |
gopMismatch |
The primary and backup streams use different keyframe frequencies. | Set both streams to the same interval, preferably 2 seconds. |
| Instability at the recommended bitrate | The upload connection or encoder may not sustain the selected bitrate. | Test the connection and stream before going live. Choose a rate the system can maintain consistently rather than treating YouTube’s recommendation as a guarantee. |
| The encoder’s frame-count setting does not match the expected interval | The configured or reported frame rate may differ from exactly 60fps, or the tool may define GOP length differently. | Use the interval-in-seconds setting where possible; otherwise verify the resulting keyframe frequency in stream health. |
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