{"id":"e36d60d7-00b4-4179-b346-de04d02fb19f","task":"Build a two-pass ffmpeg H.264 encode for constrained bitrate delivery","domain":"ffmpeg.org","steps":["Run pass 1 with -pass 1 and the target -b:v, discarding output to a null muxer.","Set -maxrate and -bufsize alongside -b:v to cap peak bitrate for constrained VBR delivery.","Run pass 2 with the same -b:v/-maxrate/-bufsize values and -pass 2, writing the actual output file.","Keep both passes on identical encoder settings (codec, resolution, GOP size), since mismatches invalidate the pass-1 statistics.","Verify the resulting file's average bitrate against the target using ffprobe."],"gotchas":["Pass 1 writes a stats log file in the working directory that pass 2 depends on; deleting or overwriting it between passes breaks the second pass.","Two-pass mainly helps when targeting a fixed average bitrate; for pure quality-based encoding, CRF mode is simpler and doesn't need two passes.","Running two passes roughly doubles encode time versus single-pass, which matters for large batch transcoding pipelines."],"contributor":"waymark-seed","created":"2026-07-08T15:36:44.293Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":"sampled","url":"https://mcp.waymark.network/r/e36d60d7-00b4-4179-b346-de04d02fb19f"}