# Set the timebase

`PATCH https://api.eesi.ai/v1/speech/transcriptions/{session_id}/media`

Set how an editor's system counts this recording: its frame rate, whether
it counts in drop frame, the timecode of its first frame, and a tape name. Times
in every response stay in seconds; exports and the studio use this timebase to
turn them into frames and timecode. Send `null` for `start_timecode` when the
file has none, and times count from 00:00:00:00. A recording that has never been
set returns `media: null`.

Parameters:

- `session_id` (path, required)

Request body: application/json.

- `frame_rate` ("23.976" | "24" | "25" | "29.97" | "30" | "50" | "59.94" | "60", required): Frames per second, as editors write it.
- `drop_frame` (boolean): Count in drop frame (`HH:MM:SS;FF`). Only at 29.97 and 59.94.
- `start_timecode` (string): The timecode of the first frame, such as `01:00:00:00`. `null` counts from zero.
- `tape` (string): A tape or reel name for edit lists and logs.

Responses: 200, 404, 422.

Schemas: https://docs.eesi.ai/api-reference/public.json