> ## Documentation Index > Fetch the complete documentation index at: https://docs.nano-gpt.com/llms.txt > Use this file to discover all available pages before exploring further. # Video Input > Send videos to compatible text and multimodal models through Chat Completions, Responses, or Messages. Video input lets compatible text and multimodal models understand a video. It is separate from [video generation](/api-reference/endpoint/video-generation): this guide covers video sent as input, not video creation, editing, or video-to-video generation. ## Choose a compatible model Request the detailed model catalog and select a model that advertises video input: ```http theme={null} GET /api/v1/models?detailed=true ``` Look for additive capability fields such as: ```json theme={null} { "architecture": { "input_modalities": ["text", "image", "video"] }, "capabilities": { "video_input": true } } ``` An explicitly selected model without video capability is rejected before provider dispatch and billing. Automatic fallback keeps only routes that preserve video input. ## Chat Completions Use the canonical OpenAI-compatible `video_url` content part with `POST /api/v1/chat/completions`: ```json theme={null} { "model": "google/gemini-3.1-flash-lite", "messages": [{ "role": "user", "content": [ { "type": "text", "text": "Describe this clip." }, { "type": "video_url", "video_url": { "url": "https://cdn.example.com/clip.mp4", "detail": "auto" } } ] }] } ``` `video_url.url` may be a public HTTPS URL or a `data:video/*;base64,...` URL. `detail` accepts `auto`, `low`, or `high` where the selected route supports it. The endpoint accepts compatibility aliases (`input_video`, direct `video`, and safely identifiable `input_file`/`file` blocks), but new integrations should emit `video_url`. A file block is classified as video only when NanoGPT can identify it from a `video/*` MIME type, a video data URL, or a recognized video filename/URL extension. Do not use an opaque file reference for video. See [Chat Completions](/api-reference/endpoint/chat-completion#video-input) for endpoint-specific examples. ## Responses Use `input_video` inside a message content array with `POST /api/v1/responses`: ```json theme={null} { "model": "google/gemini-3.1-flash-lite", "input": [{ "type": "message", "role": "user", "content": [ { "type": "input_text", "text": "Summarize the action." }, { "type": "input_video", "video_url": "data:video/mp4;base64,AAAA..." } ] }] } ``` Chat-style `video_url` is accepted as a compatibility alias. `input_file` is accepted as video only when its MIME type, data URL, or recognized filename/URL extension safely identifies video. PDFs, audio files, and unknown or opaque files are not silently treated as video. An opaque `file_id` is not resolved for Responses video input and returns `video_file_id_not_supported`. Responses Batch is separate and currently rejects video inputs. This change does not add video support to Batch. See [Responses](/api-reference/endpoint/responses#video-input) for the full endpoint contract. ## Anthropic Messages Use an Anthropic `video` content block with `POST /api/v1/messages`. For inline bytes, use the base64 source form: ```json theme={null} { "model": "google/gemini-3.1-flash-lite", "max_tokens": 512, "messages": [{ "role": "user", "content": [ { "type": "text", "text": "What happens in this clip?" }, { "type": "video", "source": { "type": "base64", "media_type": "video/mp4", "data": "AAAA..." } } ] }] } ``` For URL transport, use: ```json theme={null} { "type": "video", "source": { "type": "url", "url": "https://cdn.example.com/clip.mp4", "media_type": "video/mp4" } } ``` A `document` compatibility block with a `video/*` source is normalized as video. A document with `application/pdf` remains a document. Use `type: "video"` for new integrations. See [Messages](/api-reference/endpoint/messages#video-block) for endpoint-specific examples. ## Sources, limits, and security * Public remote sources must use HTTPS. Plain HTTP and other schemes are rejected. * Inline sources must be valid `data:video/*;base64,...` URLs, or raw base64 in an established direct field such as Anthropic `source.data` or a video-typed `input_file.file_data`. * Routes that fetch or materialize video apply SSRF protections, validate the fetched content type, allow at most 2 video attachments, and limit each attachment to 20 MB by default. Provider pass-through routes may impose stricter codec, duration, or size limits. * NanoGPT does not publish one universal duration or token conversion limit. Video remains a distinct modality for routing and billing; when duration metadata is unavailable, a conservative estimate may be reconciled against provider-reported usage. ## Segment selection `start_offset` and `end_offset` are measured in seconds and validated as finite, non-negative numbers (`end_offset` must be greater than `start_offset`). No current public text-model route can reliably honor these fields, so valid offsets return `video_segment_not_supported`; invalid ranges return `invalid_video_segment`. Do not present segment selection as supported. ## YouTube URLs YouTube pass-through is model- and route-dependent. An applicable direct Gemini route may accept a public YouTube URL. A route that would need NanoGPT to fetch or materialize it returns `youtube_video_route_not_supported`. NanoGPT does not download or scrape YouTube for video input. The separate opt-in YouTube transcript feature is not video understanding. ## Validation errors Video errors use the endpoint's normal OpenAI- or Anthropic-compatible error envelope. Common `400` codes include: | Code | Meaning | | ----------------------------------- | ----------------------------------------------------------------------------------------------------------------------- | | `video_input_not_supported` | The selected model does not support video input. | | `invalid_video_url_scheme` | A non-HTTPS remote source was used. Chat Completions may expose `video_attachment_url_invalid` as an established alias. | | `invalid_video_data_url` | The data URL is malformed or is not a video data URL. | | `invalid_video_base64` | Inline base64 is malformed. | | `invalid_video_mime_type` | An explicit non-video MIME type was used for video content. | | `missing_video_source` | The content block has no usable URL or data. | | `video_file_id_not_supported` | An unresolved uploaded-file reference was used. | | `video_attachment_too_large` | A materialized attachment exceeded the route limit. | | `video_attachment_limit_exceeded` | Too many materialized video attachments were supplied. | | `invalid_video_segment` | Segment offsets are invalid. | | `video_segment_not_supported` | The selected route cannot honor segment selection. | | `youtube_video_route_not_supported` | The selected route cannot accept the YouTube URL directly. |