[don4325]

Problem

HybridCameraVideoOutput.setBitRate(bitRate:for:) reads the connection's current codec from
output.outputSettings(for:) and applies the bit-rate to that codec. On a format whose default
movie codec is ProRes (the 10-bit 4:2:2 formats of the Pro iPhones) the connection reports
ProRes and supportedOutputSettingsKeys(for:) does not include AVVideoCompressionPropertiesKey,
so the guard in setOutputSettings(bitRate:codec:for:) logs an error and returns. The
targetBitRate the caller asked for is dropped silently and the recorder keeps writing ProRes.

Observed on an iPhone 17 Pro Max (iOS 27.0.1): the rear camera negotiated a 10-bit 4:2:2 format,
and a recording with targetBitRate set wrote 33.1 MB in 1.03 s (about 257 Mbps) until
maxFileSize stopped the take. The only log line was the "cannot use custom bit-rate" error.

Fix

• compressedCodec(preferring:): an HEVC/H.264 allow-list. Keep the current codec when it is one
  of those and the output offers it; otherwise pick the first of HEVC, H.264 that
  availableVideoCodecTypes contains; return nil when neither is offered, in which case
  setBitRate logs and leaves the connection untouched (setting a codec the output does not offer
  raises). An allow-list rather than a ProRes deny-list because any other codec (JPEG, or one the
  converter does not know) would drop the bit-rate the same way.
• setOutputSettings(bitRate:codec:for:) now applies the codec on its own before reading
  supportedOutputSettingsKeys(for:), because the supported keys are reported for the
  connection's current codec, and a ProRes connection does not list compression properties
  until it has been moved to a compressed one.

A targetBitRate is a request for a compressed codec, so this does not change behaviour for
the common H.264/HEVC formats: there the current codec is already compressed and is kept.

Verification

• swift format --configuration config/.swift-format on the file produces no diff.
• The resulting file is byte-identical to the one we carry as a pnpm patch on
  react-native-vision-camera@5.2.3. That patch is in review and has not yet reached a device;
  the production evidence above is of the defect, not of the fix.
• No Xcode build was run while preparing this branch.

Limits

• The explicit setOutputSettings(settings:) path (user-chosen codec) is untouched; if a user
  explicitly selects ProRes and also sets targetBitRate, the bit-rate call will move the
  codec to HEVC. Happy to gate on "codec was not explicitly selected" if you prefer.
• Not exercised on a device while preparing this branch beyond the production evidence above.

🤖 Generated with Claude Code

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