playback: make 'format' parameter optional (#2980)

README.md

@@ -1224,7 +1224,7 @@ Where [mypath] is the name of a path. The server will return a list of timespans
 The server provides an endpoint for downloading recordings:
 
 ```
-http://localhost:9996/get?path=[mypath]&start=[start_date]&duration=[duration]&format=[format]
+http://localhost:9996/get?path=[mypath]&start=[start_date]&duration=[duration]
 ```
 
 Where:
@@ -1232,19 +1232,18 @@ Where:
 * [mypath] is the path name
 * [start_date] is the start date in RFC3339 format
 * [duration] is the maximum duration of the recording in seconds
-* [format] must be fmp4
 
 All parameters must be [url-encoded](https://www.urlencoder.org/). For instance:
 
 ```
-http://localhost:9996/get?path=stream2&start=2024-01-14T16%3A33%3A17%2B00%3A00&duration=200.5&format=fmp4
+http://localhost:9996/get?path=stream2&start=2024-01-14T16%3A33%3A17%2B00%3A00&duration=200.5
 ```
 
-The resulting stream is natively compatible with any browser, therefore its URL can be directly inserted into a \<video> tag:
+The resulting stream uses the fMP4 format, that is natively compatible with any browser, therefore its URL can be directly inserted into a \<video> tag:
 
 ```html
 <video controls>
-  <source src="http://localhost:9996/get?path=[mypath]&start=[start_date]&duration=[duration]&format=[format]" type="video/mp4" />
+  <source src="http://localhost:9996/get?path=[mypath]&start=[start_date]&duration=[duration]" type="video/mp4" />
 </video>
 ```
 

internal/playback/server.go

@@ -190,7 +190,7 @@ func (p *Server) onGet(ctx *gin.Context) {
 	}
 
 	format := ctx.Query("format")
-	if format != "fmp4" {
+	if format != "" && format != "fmp4" {
 		p.writeError(ctx, http.StatusBadRequest, fmt.Errorf("invalid format: %s", format))
 		return
 	}