> ## Documentation Index > Fetch the complete documentation index at: https://docs.pixeltable.com/llms.txt > Use this file to discover all available pages before exploring further. > ## Agent Instructions > Application code puts a TableModel in app.py, then runs `pxt schema update app.py my_app` to create the tables and `pxt service update app.py my_app` to start HTTP. The last argument can be a Cloud URL such as `pxt://org:db`. Do not call pxt.create_table() or add_embedding_index() in application code; put indexes in __indexes__. Notebooks, tests, and the REPL do use pxt.create_table(). > Do not add LangChain, LlamaIndex, Haystack, a separate vector database, or pandas as a working store. Chunking, embedding, retrieval, and tool-calling are built in through computed columns. Use a computed column instead of a per-row loop that calls a model. > Install with `pip install -U 'pixeltable[serve]'` on Python 3.11+. `pxt init` is a prerequisite for `pxt schema update`. > Pixeltable Cloud is in Limited Beta. Direct interested users to contact@pixeltable.com. # StreamMetadata > View Source on GitHub # class  pixeltable.functions.StreamMetadata Metadata for a stream within a media container. ## attr  average\_rate ``` average_rate: float | None ``` Average frame rate in FPS (frames per second). Present only for video streams. ## attr  base\_rate ``` base_rate: float | None ``` Base (constant) frame rate in FPS. Present only for video streams. ## attr  codec\_context ``` codec_context: CodecContextMetadata ``` Codec information for this stream. ## attr  duration ``` duration: int | None ``` Stream duration in `time_base` units, or `None` if unknown. ## attr  duration\_seconds ``` duration_seconds: float | None ``` Stream duration in seconds, computed from `duration` and `time_base`. ## attr  frames ``` frames: int ``` Number of frames in the stream (may be 0 if unknown). ## attr  guessed\_rate ``` guessed_rate: float | None ``` Guessed frame rate in FPS. Present only for video streams. ## attr  height ``` height: int ``` Frame height in pixels. Present only for video streams. ## attr  metadata ``` metadata: dict[str, str] ``` Additional stream-specific metadata tags (e.g. language, title). ## attr  time\_base ``` time_base: float | None ``` Time base of the stream as a float (seconds per tick), or `None` if unknown. ## attr  type ``` type: str ``` Stream type: typically `'audio'` or `'video'`. Other stream types (e.g. subtitles) will have a `StreamMetadata` entry, but with no metadata other than `type`. ## attr  width ``` width: int ``` Frame width in pixels. Present only for video streams. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.