Consumption Reporting - Support for mediaConsumed, startTime and duration in ConsumptionReportingUnit

[dsilhavy]

Description

As part of the ConsumptionReportingUnit type as defined in 26.512 Table 11.3.3.2 the mediaConsumed property identifies the consumed media. In the case of DASH, the value of the Representation@id attribute shall be quoted. Moreover, the startTime and the duration property define the time when a consumption reporting unit started and the duration of a specific consumption unit respectively.

Implementation

Exoplayer exposes the onDownstreamFormatChanged callback to get a notification when a Representation is switched. As media segments are not multiplexed we get an individual event for video and audio segments. Following up the discussion in 5G-MAG/rt-5gms-media-session-handler#3 we decided to report the currently selected Representation as long as a new one is selected:

If the same Representation is still being consumed when it's time to send the next consumption report, I would say that this Consumption Reporting Unit is repeated as the first one in that next report, with the same startTime as before, but a longer duration.

For that reason, we need to maintain the mime type of each Representation. A switch of the video Representation should not affect the reporting of the audio Representation consumption.

Example

Based on the implementation in #51. Note that mimeType and finished are added for convenience and will be removed for the final report.

Playback start

consumptionReportingUnits: [
    {
      mediaConsumed: 'v3_257',
      mediaEndpointAddress: null,
      startTime: '2023-09-27T11:06:35Z',
      duration: 1,
      locations: null,
      mimeType: 'video/mp4',
      finished: false
    },
    {
      mediaConsumed: 'v4_258',
      mediaEndpointAddress: null,
      startTime: '2023-09-27T11:06:35Z',
      duration: 1,
      locations: null,
      mimeType: 'audio/mp4',
      finished: false
    }
  ]

Representation Switch

consumptionReportingUnits: [
    {
      mediaConsumed: 'v3_257',
      mediaEndpointAddress: null,
      startTime: '2023-09-27T11:06:35Z',
      duration: 12,
      locations: null,
      mimeType: 'video/mp4',
      finished: true
    },
    {
      mediaConsumed: 'v4_258',
      mediaEndpointAddress: null,
      startTime: '2023-09-27T11:06:35Z',
      duration: 21,
      locations: null,
      mimeType: 'audio/mp4',
      finished: false
    },
    {
      mediaConsumed: 'v7_257',
      mediaEndpointAddress: null,
      startTime: '2023-09-27T11:06:47Z',
      duration: 9,
      locations: null,
      mimeType: 'video/mp4',
      finished: false
    }
  ]

Removal of finished entry

consumptionReportingUnits: [
    {
      mediaConsumed: 'v4_258',
      mediaEndpointAddress: null,
      startTime: '2023-09-27T11:06:35Z',
      duration: 31,
      locations: null,
      mimeType: 'audio/mp4',
      finished: false
    },
    {
      mediaConsumed: 'v7_257',
      mediaEndpointAddress: null,
      startTime: '2023-09-27T11:06:47Z',
      duration: 19,
      locations: null,
      mimeType: 'video/mp4',
      finished: false
    }
  ]

[dsilhavy]

Implemented according to the example above in #51