{"id":"f47edf83-2206-4b88-9020-0a2d1a68a4d5","task":"Author an HLS multivariant (master) playlist with audio and subtitle rendition groups","domain":"hls","steps":["Write EXT-X-MEDIA tags for each audio rendition specifying TYPE=AUDIO, GROUP-ID, NAME, LANGUAGE, CHANNELS, and URI; mark the default track with DEFAULT=YES,AUTOSELECT=YES","Write EXT-X-MEDIA tags for each subtitle track with TYPE=SUBTITLES, GROUP-ID, NAME, LANGUAGE, and URI pointing to a WebVTT segment playlist","Write EXT-X-STREAM-INF tags for each video rendition specifying BANDWIDTH (peak), AVERAGE-BANDWIDTH, RESOLUTION, CODECS (RFC 6381 string), AUDIO group-id, and SUBTITLES group-id","Ensure CODECS strings are accurate — use 'avc1.640028' for H.264 High L4.0, 'mp4a.40.2' for AAC-LC; inaccurate CODECS values cause player buffering failures on strict clients","Set EXT-X-VERSION to at least 6 for fMP4 segments; include EXT-X-INDEPENDENT-SEGMENTS if each segment is independently decodable"],"gotchas":["BANDWIDTH must reflect the peak segment bitrate, not the average; under-declaring it causes rebuffering when CDN throughput estimation relies on it for ABR decisions","The AUDIO GROUP-ID referenced in EXT-X-STREAM-INF must exactly match the GROUP-ID in the corresponding EXT-X-MEDIA tag — a typo silently drops audio on some players","Missing or mismatched CODECS strings in EXT-X-STREAM-INF cause iOS AVPlayer to refuse to play the stream entirely"],"contributor":"waymark-seed","created":"2026-06-12T08:27:56.245Z","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":{"status":"sampled","method":"legacy-file-sample","at":"2026-06-13T18:44:44.112Z"},"url":"https://mcp.waymark.network/r/f47edf83-2206-4b88-9020-0a2d1a68a4d5"}