Fix HDR start crash: pick the capture pixel format after the output attaches#82
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Every HDR stream start aborted (issue #81): x420 was assigned to the video output's videoSettings before the output joined the session, and a detached output only advertises the generic 8-bit formats — setting a format outside availableVideoPixelFormatTypes raises an NSException Swift cannot catch. The output now attaches first, x420 is gated on actually appearing in the available list, and when it doesn't the whole graph reconfigures as SDR instead of crashing or wrapping 8-bit frames in an HLG-tagged Main10 encode. configure() returns the colour it delivered, and Streamer builds the encoder, VIDEO_CONFIG, and STATE from that instead of the requested colour, so a degrade is honest on the wire. SDR-only behaviour is unchanged. Fixes #81 Release-Bump: minor Release-Beta: true Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_015dWUcqAkNNuNELnMPS4RdT
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July 25, 2026 09:19
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What & why
Fixes #81 — every HDR stream start in v1.9.0-beta.1 aborted with an uncatchable NSException from
-[AVCaptureVideoDataOutput setVideoSettings:]. The 10-bit pixel format (x420) was assigned while the output was still detached from the capture session, and a detached output only advertises the generic 8-bit formats;x420entersavailableVideoPixelFormatTypesonly once the output is connected to a device whose active format is 10-bit.Three changes, all in the iOS app:
x420is gated on actually appearing inavailableVideoPixelFormatTypes; if it doesn't, the whole capture graph reconfigures as SDR (nested begin/commit, full re-run) instead of crashing — or worse, silently wrapping 8-bit frames in an HLG-tagged Main10 encode that would reach OBS with wrong colours.configure()now returns the colour it actually delivered, andStreamerbuilds the encoder, VIDEO_CONFIG, and STATE from that instead of the requested colour, so a degrade is honest on the wire.SDR-only behaviour is unchanged (
420vis always in the generic list, which is why this ordering never bit before).How it was tested
syntax-check.sh; the full type check runs in CI's macOS job.🤖 Generated with Claude Code
https://claude.ai/code/session_015dWUcqAkNNuNELnMPS4RdT
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