Android Video Frames Data Source

Overview

A Perfetto data source that captures screen frames as JPEG images, emitted as TrackEvent instants with a VideoFrame sub-message. JPEG data is stored in dedicated blob storage (not base64 in args) for efficient access.

This data source lives in the Android tree (frameworks/base), not in this repo. The Perfetto-side changes (trace processor, UI plugin, tests) are here.

Proto

VideoFrame is defined in protos/perfetto/trace/android/video_frame.proto and carried as TrackEvent.video_frame (field 57).

Fields:

• frame_number (uint64): sequential frame number
• jpg_image (bytes): JPEG image data

Track identity and display name come from standard TrackDescriptor machinery — each stream uses its own track_uuid and TrackDescriptor.name.

Emitting video frames

# One track descriptor per stream.
packet {
  trusted_packet_sequence_id: 1
  track_descriptor { uuid: 100  name: "Front Camera" }
}

# One TrackEvent per frame.
packet {
  timestamp: 1000000000
  trusted_packet_sequence_id: 1
  track_event {
    type: TYPE_INSTANT
    track_uuid: 100
    video_frame {
      frame_number: 0
      jpg_image: <jpeg bytes>
    }
  }
}

Test data

• Trace generator: test/trace_processor/diff_tests/parser/android/generate_video_trace.py
• Diff tests: test/trace_processor/diff_tests/parser/android/tests.py (see test_video_frame_*)