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Merged
ptpt merged 3 commits into from
Jun 23, 2025
Merged

improve: handle NMEA GGA/GLL/RMC in blackvue videos #757

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8cf6874
improve: handle NMEA GGA/GLL/RMC
ptpt Jun 23, 2025
421d1cd
tests
ptpt Jun 23, 2025
88ff58b
tests
ptpt Jun 23, 2025
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63 changes: 45 additions & 18 deletions mapillary_tools/blackvue_parser.py
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -17,11 +17,11 @@
NMEA_LINE_REGEX = re.compile(
rb"""
^\s*
\[(\d+)\] # timestamp
\[(\d+)\] # Timestamp
\s*
(\$\w{5}.*) # nmea line
(\$\w{5}.*) # NMEA message
\s*
(\[\d+\])? # strange timestamp
(\[\d+\])? # Strange timestamp
\s*$
""",
re.X,
Expand Down Expand Up @@ -118,8 +118,16 @@ def _parse_gps_box(gps_data: bytes) -> T.Generator[geo.Point, None, None]:
"""
>>> list(_parse_gps_box(b"[1623057074211]$GPGGA,202530.00,5109.0262,N,11401.8407,W,5,40,0.5,1097.36,M,-17.00,M,18,TSTR*61"))
[Point(time=1623057074211, lat=51.150436666666664, lon=-114.03067833333333, alt=1097.36, angle=None)]

>>> list(_parse_gps_box(b"[1629874404069]$GNGGA,175322.00,3244.53126,N,11710.97811,W,1,12,0.84,17.4,M,-34.0,M,,*45"))
[Point(time=1629874404069, lat=32.742187666666666, lon=-117.1829685, alt=17.4, angle=None)]

>>> list(_parse_gps_box(b"[1629874404069]$GNGLL,4404.14012,N,12118.85993,W,001037.00,A,A*67"))
[Point(time=1629874404069, lat=44.069002, lon=-121.31433216666667, alt=None, angle=None)]

>>> list(_parse_gps_box(b"[1629874404069]$GNRMC,001031.00,A,4404.13993,N,12118.86023,W,0.146,,100117,,,A*7B"))
[Point(time=1629874404069, lat=44.06899883333333, lon=-121.31433716666666, alt=None, angle=None)]

>>> list(_parse_gps_box(b"[1623057074211]$GPVTG,,T,,M,0.078,N,0.144,K,D*28[1623057075215]"))
[]
"""
Expand All @@ -128,24 +136,43 @@ def _parse_gps_box(gps_data: bytes) -> T.Generator[geo.Point, None, None]:
if match is None:
continue
nmea_line_bytes = match.group(2)
if nmea_line_bytes.startswith(b"$GPGGA") or nmea_line_bytes.startswith(
b"$GNGGA"
):
try:
nmea_line = nmea_line_bytes.decode("utf8")
except UnicodeDecodeError:
continue
try:
nmea = pynmea2.parse(nmea_line)
except pynmea2.nmea.ParseError:

if not nmea_line_bytes:
continue

try:
nmea_line = nmea_line_bytes.decode("utf8")
except UnicodeDecodeError:
continue

if not nmea_line:
continue

try:
message = pynmea2.parse(nmea_line)
except pynmea2.nmea.ParseError:
continue

epoch_ms = int(match.group(1))

# https://tavotech.com/gps-nmea-sentence-structure/
if message.sentence_type in ["GGA"]:
if not message.is_valid:
continue
if not nmea.is_valid:
yield geo.Point(
time=epoch_ms,
lat=message.latitude,
lon=message.longitude,
alt=message.altitude,
angle=None,
)
elif message.sentence_type in ["RMC", "GLL"]:
if not message.is_valid:
continue
epoch_ms = int(match.group(1))
yield geo.Point(
time=epoch_ms,
lat=nmea.latitude,
lon=nmea.longitude,
alt=nmea.altitude,
lat=message.latitude,
lon=message.longitude,
alt=None,
angle=None,
)
17 changes: 7 additions & 10 deletions mapillary_tools/process_sequence_properties.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -24,24 +24,21 @@ def split_sequence_by(
"""
output_sequences: list[list[SeqItem]] = []

seq = iter(sequence)

prev = next(seq, None)
if prev is None:
return output_sequences

output_sequences.append([prev])
if sequence:
output_sequences.append([sequence[0]])

for cur in seq:
for prev, cur in geo.pairwise(sequence):
# invariant: prev is processed
if should_split(prev, cur):
output_sequences.append([cur])
else:
output_sequences[-1].append(cur)
prev = cur
# invariant: cur is processed

assert sum(len(s) for s in output_sequences) == len(sequence)
assert sum(len(s) for s in output_sequences) == len(sequence), (
output_sequences,
sequence,
)

return output_sequences

Expand Down
49 changes: 30 additions & 19 deletions tests/unit/test_blackvue_parser.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -7,36 +7,33 @@

def test_parse_points():
gps_data = b"""
# GGA
[1623057130221]$GPGGA,201205.00,3853.16949,N,07659.54604,W,2,10,0.82,7.7,M,-34.7,M,,0000*6F
[1623057130221]$GPGGA,201205.00,3853.16949,N,07659.54604,W,2,10,0.82,7.7,M,-34.7,M,,0000*6F

# GGA
[1623057129253]$GPGGA,201204.00,3853.16945,N,07659.54371,W,2,10,0.99,10.2,M,-34.7,M,,0000*5C
[1623057129253]$GPGGA,201204.00,3853.16945,N,07659.54371,W,2,10,0.99,10.2,M,-34.7,M,,0000*5C

[1623057129253]$GPGSA,A,3,19,02,06,12,17,09,05,20,04,25,,,1.83,0.99,1.54*0C
[1623057129253]$GPGSA,A,3,19,02,06,12,17,09,05,20,04,25,,,1.83,0.99,1.54*0C

[1623057129253]$GPGSV,3,1,12,02,67,331,39,04,08,040,21,05,28,214,30,06,53,047,31*71
[1623057129253]$GPGSV,3,1,12,02,67,331,39,04,08,040,21,05,28,214,30,06,53,047,31*71

[1623057129253]$GPGSV,3,2,12,09,23,071,28,12,48,268,41,17,17,124,26,19,38,117,35*78
[1623057129253]$GPGSV,3,2,12,09,23,071,28,12,48,268,41,17,17,124,26,19,38,117,35*78

[1623057129253]$GPGSV,3,3,12,20,23,221,35,25,26,307,39,46,20,244,35,51,35,223,40*72
[1623057129253]$GPGSV,3,3,12,20,23,221,35,25,26,307,39,46,20,244,35,51,35,223,40*72

[1623057129253]$GPGLL,3853.16945,N,07659.54371,W,201204.00,A,D*70
[1623057129255]$GPGLL,3853.16945,N,07659.54371,W,201204.00,A,D*70

[1623057129253]$GPRMC,201205.00,A,3853.16949,N,07659.54604,W,5.849,284.43,070621,,,D*76
[1623057129256]$GPRMC,201205.00,A,3853.16949,N,07659.54604,W,5.849,284.43,070621,,,D*76

[1623057129253]$GPVTG,284.43,T,,M,5.849,N,10.833,K,D*08[1623057130221]
[1623057129257]$GPVTG,284.43,T,,M,5.849,N,10.833,K,D*08[1623057130221]

# GGA
[1623057130221]$GPGGA,201205.00,3853.16949,N,07659.54604,W,2,10,0.82,7.7,M,-34.7,M,,0000*6F
[1623057130258]$GPGGA,201205.00,3853.16949,N,07659.54604,W,2,10,0.82,7.7,M,-34.7,M,,0000*6F

# invalid line
[1623057130221]$GPGGA,**&^%$%$&(&(*(&&(^^*^*^^*&^&*))))
# invalid line
[1623057130221]$GPGGA,**&^%$%$&(&(*(&&(^^*^*^^*&^&*))))

# invalid line
[1623057130221]$GPGGA,\x00\x00\x1c\xff
# invalid line
[1623057130221]$GPGGA,\x00\x00\x1c\xff

[1623057130221]$GPGSA,A,3,19,02,06,12,17,09,05,20,04,25,,,1.65,0.82,1.43*08
[1623057130221]$GPGSA,A,3,19,02,06,12,17,09,05,20,04,25,,,1.65,0.82,1.43*08
"""

box = {"type": b"free", "data": [{"type": b"gps ", "data": gps_data}]}
Expand All @@ -48,9 +45,23 @@ def test_parse_points():
time=0.0, lat=38.8861575, lon=-76.99239516666667, alt=10.2, angle=None
),
geo.Point(
time=0.968, lat=38.88615816666667, lon=-76.992434, alt=7.7, angle=None
time=0.002,
lat=38.8861575,
lon=-76.99239516666667,
alt=None,
angle=None,
),
geo.Point(
time=0.003,
lat=38.88615816666667,
lon=-76.992434,
alt=None,
angle=None,
),
geo.Point(
time=0.968, lat=38.88615816666667, lon=-76.992434, alt=7.7, angle=None
),
geo.Point(
time=1.005, lat=38.88615816666667, lon=-76.992434, alt=7.7, angle=None
),
] == list(info.gps or [])