{ "id": "captions-retime-convert", "name": "Retime and convert literal captions", "description": "Convert a strict plain SRT/WebVTT caption file with caller-supplied rational time scaling and offset, returning canonical caption text and an exact cue timing map.", "category": "text", "priceUsd": "0.005", "pricingStatus": "proposed-unverified", "pricing": { "unit": "one successful operation call", "proposedNominalUsd": "0.005", "sixDecimalTokenBaseUnits": "5000", "subscription": false, "includesPayerWalletOrNetworkFees": false, "liveQuoteVerified": false, "condition": "Actual SDK challenge is authoritative only within the caller's explicit authorization; configured six-decimal token peg is an operator assertion, not a conversion guarantee." }, "intents": [ "Convert supplied plain SRT subtitles to WebVTT or WebVTT to SRT", "Shift subtitle cue times by a known offset or correct constant drift using explicit rational scaling" ], "whenToUse": [ "Supplied literal caption text with explicit hour timestamps and a known affine millisecond transform" ], "whenNotToUse": [ "Transcription, translation, speaker identification, media access, inferred sync anchors or guaranteed audiovisual alignment", "Rich captions, markup, entities, whitespace-only cue lines, cue settings, STYLE, REGION, NOTE or arbitrary WebVTT identifiers", "Fetching, uploading, sending, writing files, accessing media or changing external state" ], "capabilities": [ "Exact BigInt rational endpoint transformation with one nearest-ties-even millisecond rounding", "Canonical LF timestamps and cue indexes, preserved literal text and source/output timing map", "Atomic rejection of unsupported grammar, unordered starts, range violations or collapsed durations", "Deterministic supplied-input-only inert artifact with no network, clock or randomness" ], "limits": { "inputBytes": 100000, "outputBytes": 400000, "jsonNodes": 12000, "depth": 20, "profile": "literal-captions-affine-ms-v1", "sourceBytes": 60000, "cues": 1000, "totalCueTextBytes": 40000, "linesPerCue": 20, "captionOutputBytes": 100000, "maximumTimeMs": 359999999, "maximumScalePart": 1000000, "scaleRange": "1/1000 through 1000", "webvttIds": "all absent or all contiguous numeric 1..N" }, "related": [ "text-bytes-transcode", "zip-store-compose", "timestamp-convert" ], "errorCodes": [ "INPUT_LIMIT", "OUTPUT_LIMIT", "COMPLEXITY_LIMIT", "INVALID_JSON", "INVALID_NUMBER", "INVALID_UNICODE", "UNSAFE_KEY", "CAPTION_SOURCE_LIMIT", "CAPTION_SCALE_RANGE", "CAPTION_SYNTAX", "CAPTION_TEXT_PROFILE", "CAPTION_CUE_LIMIT", "CAPTION_DURATION", "CAPTION_ORDER", "CAPTION_TEXT_LIMIT", "CAPTION_TIME_RANGE", "CAPTION_OUTPUT_LIMIT" ], "requirementsProfile": { "format": "declared-requirements-v1", "facts": { "execution.suppliedCode": false, "execution.remoteMutation": false, "execution.llmInference": false, "execution.paidMcp": false, "verification.semanticTruth": false, "verification.sourceAuthenticity": false, "verification.liveVulnerabilities": false, "numbers.arbitraryPrecisionJson": false, "numbers.model": "ieee754-binary64", "privacy.requestBodyPersisted": false, "execution.deterministic": true, "execution.networkAccess": false, "privacy.resultBodyPersisted": false, "payment.x402": true, "payment.mpp": true, "operation.id": "captions-retime-convert", "operation.category": "text", "limit.httpRequestBytes": 131072, "limit.requestBytes": 100000, "limit.responseBytes": 524288, "limit.resultBytes": 400000, "limit.jsonDepth": 20, "limit.jsonNodes": 12000, "captions.profile": "literal-captions-affine-ms-v1", "captions.maxCues": 1000, "captions.maxSourceBytes": 60000, "captions.maxCueTextBytes": 40000, "captions.maxLinesPerCue": 20, "captions.maxOutputTextBytes": 100000, "captions.maxTimestampMs": 359999999, "captions.rounding": "nearest-ties-even", "captions.transcription": false, "captions.translation": false, "captions.mediaAlignmentVerified": false, "captions.richMarkup": false, "captions.whitespaceOnlyCueLines": false, "captions.fullSrtOrWebvttConformance": false, "input.text.maxLength": 60000, "input.text.minLength": 1 }, "unknownPolicy": "Undeclared requirements are unknown, never compatible. Matching declared facts does not establish semantic fit or input validity.", "preflight": "/preflight" }, "documentation": "/reference/tools/captions-retime-convert.md", "serviceContract": "/reference/services/captions-retime-convert.json", "errors": [ { "status": 400, "meaning": "Malformed JSON, missing/invalid idempotency key, or payment identifier mismatch", "retry": "Correct the request before payment" }, { "status": 402, "meaning": "Payment challenge or rejected payment", "retry": "Use official protocol SDK; inspect payment outcome before another payment" }, { "status": 409, "meaning": "Idempotency conflict, duplicate proof, or PAYMENT_UNCERTAIN", "retry": "Keep original key, body, and proof; reconcile uncertainty with operator; never blindly repay" }, { "status": 413, "meaning": "Input or generated output too large", "retry": "Reduce input; no payment attempted for validation failure" }, { "status": 415, "meaning": "Unsupported media type or compression", "retry": "Send uncompressed application/json" }, { "status": 422, "meaning": "Schema or service-specific semantic validation failure", "retry": "Correct input using returned error code; no payment attempted" }, { "status": 429, "meaning": "Request/payment-attempt rate exceeded", "retry": "Wait for rate limit window; preserve existing payment identity" }, { "status": 503, "meaning": "Payment configuration/provider/state unavailable, or live DNS preparation failed before settlement", "retry": "Check readiness; DNS preparation failures may retry the identical key/body/credential only; uncertainty requires reconciliation" } ], "numericPrecision": "JavaScript IEEE-754 numbers; use strings for large integer IDs/exact decimals where the schema accepts strings. No lossless numeric parsing.", "paymentWorkflow": { "discoveryOnly": false, "supportedProtocols": [ "x402", "mpp" ], "x402": { "credentialHeader": "PAYMENT-SIGNATURE", "challengeHeader": "PAYMENT-REQUIRED", "receiptHeader": "PAYMENT-RESPONSE", "version": 2, "scheme": "exact", "paymentIdentifier": "payment-identifier extension MUST equal the HTTP Idempotency-Key", "sdk": "@x402/core with @x402/evm" }, "mpp": { "supported": true, "credentialHeader": "Authorization", "challengeHeader": "WWW-Authenticate", "receiptHeader": "Payment-Receipt", "method": "tempo", "intent": "charge", "sdk": "mppx", "tokenDecimals": 6 }, "steps": [ "Check configured readiness and the exact service schema", "Generate a fresh random Idempotency-Key for this operation; never use a discovery probe fixture for purchases", "Send valid input without a credential to obtain the official protocol challenge", "Use the official SDK and authorized wallet to fulfill the challenge", "Retry only with identical key, body, protocol and credential", "On PAYMENT_UNCERTAIN stop and request operator reconciliation; never blindly pay again" ], "versionedRetries": "Request fingerprint includes service release version. Retries across a version upgrade can conflict; coordinate upgrades outside the 24-hour replay window and reconcile pending attempts.", "docs": "/llms.txt" }, "method": "POST", "paths": { "x402": "/v1/x402/captions-retime-convert", "mpp": "/v1/mpp/captions-retime-convert" }, "inputSchema": { "$schema": "https://json-schema.org/draft/2020-12/schema", "type": "object", "properties": { "from": { "type": "string", "enum": [ "srt", "webvtt" ] }, "to": { "type": "string", "enum": [ "srt", "webvtt" ] }, "text": { "type": "string", "minLength": 1, "maxLength": 60000 }, "timing": { "type": "object", "properties": { "scaleNumerator": { "type": "integer", "minimum": 1, "maximum": 1000000 }, "scaleDenominator": { "type": "integer", "minimum": 1, "maximum": 1000000 }, "offsetMs": { "type": "integer", "minimum": -359999999, "maximum": 359999999 } }, "required": [ "scaleNumerator", "scaleDenominator", "offsetMs" ], "additionalProperties": false } }, "required": [ "from", "to", "text", "timing" ], "additionalProperties": false }, "outputSchema": { "type": "object", "required": [ "operation", "version", "result", "provenance" ], "properties": { "operation": { "const": "captions-retime-convert", "type": "string" }, "version": { "const": "0.29.0", "type": "string" }, "result": { "$schema": "https://json-schema.org/draft/2020-12/schema", "type": "object", "properties": { "format": { "type": "string", "enum": [ "srt", "webvtt" ] }, "text": { "type": "string", "maxLength": 100000 }, "byteLength": { "type": "integer", "minimum": 1, "maximum": 100000 }, "cues": { "minItems": 1, "maxItems": 1000, "type": "array", "items": { "type": "object", "properties": { "inputIndex": { "type": "integer", "minimum": 0, "maximum": 999 }, "startMs": { "type": "integer", "minimum": 0, "maximum": 359999999 }, "endMs": { "type": "integer", "minimum": 0, "maximum": 359999999 }, "sourceStartMs": { "type": "integer", "minimum": 0, "maximum": 359999999 }, "sourceEndMs": { "type": "integer", "minimum": 0, "maximum": 359999999 } }, "required": [ "inputIndex", "startMs", "endMs", "sourceStartMs", "sourceEndMs" ], "additionalProperties": false } }, "rounding": { "type": "string", "const": "nearest-ties-even" } }, "required": [ "format", "text", "byteLength", "cues", "rounding" ], "additionalProperties": false }, "provenance": { "type": "object", "required": [ "inputSha256", "outputSha256", "deterministic", "externalRequests" ], "properties": { "inputSha256": { "type": "string", "pattern": "^[a-f0-9]{64}$" }, "outputSha256": { "type": "string", "pattern": "^[a-f0-9]{64}$" }, "deterministic": { "const": true }, "externalRequests": { "const": 0 } } } }, "additionalProperties": false }, "exampleInput": { "from": "srt", "to": "webvtt", "text": "1\n00:00:01,000 --> 00:00:02,500\nHello\n\n", "timing": { "scaleNumerator": 1, "scaleDenominator": 1, "offsetMs": 250 } }, "exampleResponse": { "operation": "captions-retime-convert", "version": "0.29.0", "result": { "format": "webvtt", "text": "WEBVTT\n\n1\n00:00:01.250 --> 00:00:02.750\nHello\n\n", "byteLength": 47, "cues": [ { "inputIndex": 0, "startMs": 1250, "endMs": 2750, "sourceStartMs": 1000, "sourceEndMs": 2500 } ], "rounding": "nearest-ties-even" }, "provenance": { "inputSha256": "86618830933272d3a6509644a192dbec754392cc7a3882ed00cd19de4dc7ce88", "outputSha256": "9963ea0da9e0b915bf16503d12e7c6db4c9cc690b3ec6d64f95b28f9ccc5a2cc", "deterministic": true, "externalRequests": 0 } }, "requiredHeaders": { "Content-Type": "application/json", "Idempotency-Key": "random 16–128 character operation identifier" }, "fixedExample": "/reference/examples/captions-retime-convert.json", "execution": { "deterministic": true, "externalRequests": 0, "maxExternalRequests": 0, "resultSnapshotPersisted": false, "fixedExampleIsIllustrativeSnapshot": false, "requiresPayment": true, "supportsMcpExecution": false }, "releaseSnapshot": { "format": "static-release-reference-v1", "sourceVersion": "0.29.0", "sourceRegistrySha256": "a2b5ec09bf6c38b9d2879d746a4fded374f5928b445377b0270ef6aa8e6cac65", "generatedAt": "2026-10-06T15:38:00Z", "releaseAcceptance": "not-verified-by-generator", "runtimeReadiness": "not-evaluated", "livePaymentsVerified": false, "indexingVerified": false, "apiOrigin": null, "notice": "Build-time release reference. Runtime readiness, deployment, payment settlement and external indexing are not evaluated here. Prices are proposed; this file cannot authorize execution or payment." } }