MCAP Replay

Set InitParameters::input_type to MCAP and provide a recording path. The normal grab() and retrieval loop remains unchanged.

InitParameters init;
init.input_type = INPUT_TYPE::MCAP;
init.mcap_path  = "session.mcap";

Device dev;
if (dev.open(init) != ERROR_CODE::SUCCESS) return 1;

Mat image;
SensorsData sensors;
for (;;) {
    ERROR_CODE ec = dev.grab();
    if (ec == ERROR_CODE::END_OF_BUFFER) break;   // file exhausted
    if (ec != ERROR_CODE::SUCCESS)       continue;
    dev.retrieve_image(image);
    dev.retrieve_imu(sensors);
}
dev.close();

Replay differs from a live session in four ways:

grab() returns END_OF_BUFFER when the file is exhausted, the one loop-exit condition unique to replay.
The recording’s codec overrides InitParameters::compression; the SDK decodes the format stored in the file.
Control-plane calls (health, WiFi, recording management) return INVALID_FUNCTION_CALL, since there is no device.
Timestamps are the original capture timestamps from the recording.

Both host-file and device-local recordings replay identically, since they share one schema. Recordings also open directly in Foxglove. To extract the raw H.264/H.265 elementary stream from a session, use the bundled script:

python3 sdk/linux/tools/mcap_to_video.py session.mcap session.h265

The script writes an elementary stream, not a container. Wrap it in a container to produce a playable file, for example ffmpeg -i session.h265 -c copy session.mp4.

Getting Started

Device

Command-Line Tools