fix(distributed): apply -r <fps> to single-chunk pass-through path#1053
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The v0.6.39 fix added -r <fps> to the multi-chunk concat ffmpeg invocation but didn't reach the single-chunk pass-through path, which is taken when totalFrames * fpsDen / fpsNum fits in one chunk. Result: 1-chunk renders shipped with fractional r_frame_rate (e.g. 359/12) while multi-chunk renders shipped with exact 30/1. Single-chunk path now goes through the same -r <fps> + -c copy ffmpeg invocation as the concat path, ensuring uniform exact r_frame_rate metadata across all chunk-count configurations. Adds a regression test exercising the 1-chunk path and asserting r_frame_rate === "<fpsNum>/<fpsDen>" exact.
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| const concatBody = chunkPaths | ||
| .map((path) => `file '${path.replace(/'/g, "'\\''")}'`) | ||
| .join("\n"); | ||
| writeFileSync(concatListPath, `${concatBody}\n`, "utf-8"); |
miguel-heygen
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May 24, 2026
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Review: Magi
Clean fix. The single-chunk branch is the correct approach — using -r as an output flag on a direct remux rather than trying to make the concat demuxer honor it for a one-entry list.
Verified:
-r <fps>is correctly placed as an output-side flag (after-i) with-c copy— no re-encode- Test pins
r_frame_rate === "30/1"+ 1ms duration tolerance on the 1-chunk path - Downstream audio pad/trim, mux, and faststart pipeline is unchanged and shared between both branches
- Multi-chunk path is byte-identical to the original PR #1040 code, just moved inside
else - 0-chunk edge case is pre-existing (invalid upstream state), no regression
No issues found. Ship it.
— Magi
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What
The v0.6.39 fix (#1040) added
-r <fps>to the multi-chunk concat ffmpeg invocation but didn't reach the single-chunk pass-through path. Result: 1-chunk renders ship with fractionalr_frame_rate(e.g.359/12) while multi-chunk renders ship with exact30/1.Why
Without this fix, the metadata-exactness guarantee from #1040 doesn't apply uniformly across chunk-count configurations. Downstream pipelines that consume
r_frame_ratesee inconsistent values depending on how a render plan happens to chunk.How
Single-chunk path now goes through the same
-r <fps>+-c copyffmpeg invocation as the concat path, ensuring uniform exactr_frame_ratemetadata.Test plan
r_frame_rate === "<fpsNum>/<fpsDen>"exact.