Smooth Streaming {start_time} placeholder not supported

[alfonsoramosa]

Exoplayer 2.2.0
Device: Nexus player
Android 7.1.1

Exoplayer is not working with some Smooth Streaming manifests.

That's happening when the Url for a StreamIndex has a placeholder for the start time with the format: "start_time" instead of "start time" (with an underscore between start and time).

Example:

<StreamIndex Type="audio" QualityLevels="3" TimeScale="10000000" Language="eng" Name="audio_eng" Chunks="1378" Url="QualityLevels({bitrate})/Fragments(audio_eng={start_time})">

SsManifest.java

Placeholder defined as:
private static final String URL_PLACEHOLDER_START_TIME = "{start time}";
The method buildRequestUri() is only replacing "start time", but not "start_time"
Then, the placeholder remains in the Url, causing an error response.

[ojw28]

We should also match both {bitrate} and {Bitrate} according to the spec, rather than just {bitrate} as we do currently. We'll push a fix shortly.