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Read NMEA files that log sentences without a fix, or from other talkers - #870
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The README lists NMEA among the sources that geotag videos, but no video was read from an NMEA file: process and video_process gave the video no description at all, and exited 0, so it was silently left out. Sampling fell back to the GPS in the video, which a video recorded with an external logger does not have. Read the NMEA file into a track and place it on the video exactly as a GPX track is: synced by the GPS clock of the video, or by --video_start_time, or assumed to start with the video, with the interpolation options, the coverage checks and the clipping of process. GPXVideoExtractor now reads its file through _parse_tracks(), which NMEAVideoExtractor overrides, and names the format of the file in its messages. A file that is not valid NMEA is reported as an invalid GPX file is. Interval sampling checks an NMEA track started with the video by --interpolation_use_gpx_start_time as it checks a GPX track. On an action camera video with a GPX and the same track as NMEA, process gives the same track, and video_process samples the same frames at the same positions.
Images geotagged from an NMEA file failed with a traceback when the file had an RMC sentence without a date, such as the last one of a log cut short (TypeError), or GGA sentences and no RMC sentence at all (UnboundLocalError), and a video was failed as if the file were not NMEA. A void RMC sentence, which receivers log before they acquire a fix, gave the date of their unset clock, and a GGA sentence without a fix added a point at 0, 0. Only $GP sentences were read, so a log of a receiver of several systems, which writes $GN sentences, gave no points at all. Skip RMC sentences that are void or have no date or time, and GGA sentences without a time or a fix, and read the sentences of any talker, keeping the first fix of each time, so that a receiver that logs a fix from two talkers does not give two points at the same time. GGA sentences without the date of any RMC sentence give no points, with a warning. The points read from valid files are the same.
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Stacked on #869; review the last commit.
Problem
The NMEA reader, which images and (with #869) videos share, fails on files that receivers commonly write:
TypeError; GGA sentences with no RMC sentence crashed with anUnboundLocalError. A video was failed as if the file were not NMEA.$GPsentences were read, so a log of a multi-system receiver, which writes$GNsentences, gave no points.Fix
Skip RMC sentences that are void or have no date or time, and GGA sentences without a time or a fix. Read the sentences of any talker, keeping the first fix of each time, so a receiver that logs a fix from two talkers gives one point. GGA sentences without the date of any RMC sentence give no points, with a warning. Valid files give the same points.
Verification
$GNversion of the 650-point log, and one starting with void sentences, give the same video track as the original.mypy --python-version 3.9,ruff check,ruff format --checkandusort diffare clean.