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--- dvr_api [2019/10/10 19:46]
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 ======HDHomeRun DVR development guide======
+=====Live TV=====
+<WRAP indent>
+The record engine supports buffering live TV with automatic tuner sharing.
+====API URL====
+<WRAP indent>
+<code><storage engine BaseURL>/auto/v<channel number>?<parameters></code>
+Example: <code>http://10.20.20.162:4999/auto/v2.1?<parameters></code>
+</WRAP>
+====Parameters====
+<WRAP indent>
+^ Parameter ^ Type ^ Description ^
+| ClientID | GUID | Unique ID to identify the player. |
+| SessionID | hex32 | Unique ID to identify the channel request. |
+Returns: Video stream from the requested channel.
+If the app supports multiple running instances on the same computer each instance must have a unique ClientID. The ClientID does not need to be persistent across app launches. A valid implementation is to choose a ClientID when an instance of the app is launched.
+If the app supports picture-in-picture then each "picture" must have a different ClientID so that changing channel on one "picture" does not cancel and free the tuner being used by the other "picture".
+The SessionID must be unique for each new request of a channel. This allows the record engine to differentiate between a new request vs a seek within the existing session.
+</WRAP>
+====Seeking====
+<WRAP indent>
+  - Close the existing HTTP connection that is streaming video.
+  - Issue a new HTTP request specifying the desired starting byte offset in the RANGE header. The ClientID and SessionID parameters of the URL must be the same as the original HTTP request.
+When attempting to seek beyond the current live point the record engine will return success and will indicate the actual (lower) byte position in the HTTP Content-Range response header.
+The record engine automatically limits the amount of back history that is available for a channel to avoid running the DVR out of disk space when a client is left playing a channel for an extended period of time. When attempting to seek back to a byte position that is before the oldest still-available data the record engine will return success and will indicate the actual (higher) byte position in the HTTP Content-Range response header.
+</WRAP>
+====Changing channel====
+<WRAP indent>
+  - Close the existing HTTP connection that is streaming video.
+  - Issue a new HTTP connection to request the new channel. Use the same ClientID but a new SessionID.
+The same ClientID tells the record engine that the previous channel is not longer of interest. Required to avoid tying up a new tuner with each channel change.
+The new SessionID tells the record engine that this is a new request rather than a seek request. Required to handle the situation where the user leaves live TV mode, then a short while later goes back into live TV mode.
+</WRAP>
+</WRAP>

development