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Read uint64 sample counts from hdr files #242

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73e26ce
Read uint64 sample counts from hdr files
robrui May 18, 2026
6e04805
fix: use structured dtype to read interleaved hdr entries
robrui May 18, 2026
acefe80
style: fix black formatting and mypy int type issue
robrui May 18, 2026
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13 changes: 10 additions & 3 deletions backend/src/spectre_server/core/batches/_iq_stream.py
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Original file line number Diff line number Diff line change
Expand Up @@ -86,7 +86,7 @@ class IQMetadata:
"""

center_frequencies: npt.NDArray[np.float32]
num_samples: npt.NDArray[np.int32]
num_samples: npt.NDArray[np.int64]


class _HdrFile(BatchFile[IQMetadata]):
Expand All @@ -96,8 +96,15 @@ def read(self) -> IQMetadata:

:return: A container for the metadata
"""
data = np.fromfile(self.file_path, dtype=np.float32)
return IQMetadata(data[0::2], data[1::2].astype(np.int32))
# The binary layout is [value_float32, nsamples_uint64] repeated (12 bytes per entry).
raw = np.fromfile(self.file_path, dtype=np.uint8)
entry_bytes = 12
n_entries = raw.size // entry_bytes
raw = raw[: n_entries * entry_bytes]

dt = np.dtype([("value", "<f4"), ("nsamples", "<u8")])
structured = np.frombuffer(raw.tobytes(), dtype=dt)
return IQMetadata(structured["value"], structured["nsamples"].astype(np.int64))


class _FitsFile(BatchFile[spectre_server.core.spectrograms.Spectrogram]):
Expand Down
20 changes: 10 additions & 10 deletions backend/src/spectre_server/core/events/_swept_center_frequency.py
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Original file line number Diff line number Diff line change
Expand Up @@ -43,7 +43,7 @@ def _average_over_steps(


def _compute_num_max_frames_in_step(
num_samples: npt.NDArray[np.int32], window_size: int, window_hop: int
num_samples: npt.NDArray[np.int64], window_size: int, window_hop: int
) -> int:
"""Compute the maximum number of frames for all steps, and all sweeps, in the batch."""
return get_num_spectrums(int(np.max(num_samples)), window_size, window_hop)
Expand Down Expand Up @@ -101,7 +101,7 @@ def _compute_stepped_dynamic_spectra(
window_hop: int,
num_full_sweeps: int,
num_steps_per_sweep: int,
num_samples: npt.NDArray[np.int32],
num_samples: npt.NDArray[np.int64],
) -> None:
"""For each full sweep, compute execute a short-time discrete Fourier transform on the IQ samples for each step."""
# Store the step index over all sweeps (doesn't reset each sweep).
Expand Down Expand Up @@ -159,7 +159,7 @@ def _compute_frequencies(

def _compute_times(
times: npt.NDArray[np.float32],
num_samples: npt.NDArray[np.int32],
num_samples: npt.NDArray[np.int64],
sample_rate: float,
num_full_sweeps: int,
num_steps_per_sweep: int,
Expand All @@ -176,7 +176,7 @@ def _compute_times(
end_step = (sweep_index + 1) * num_steps_per_sweep

# Update cumulative samples
cumulative_samples += np.sum(num_samples[start_step:end_step])
cumulative_samples += int(np.sum(num_samples[start_step:end_step]))


def _swept_stfft(
Expand All @@ -188,7 +188,7 @@ def _swept_stfft(
sample_rate: float,
frequency_hop: float,
center_frequencies: npt.NDArray[np.float32],
num_samples: npt.NDArray[np.int32],
num_samples: npt.NDArray[np.int64],
) -> tuple[npt.NDArray[np.float32], npt.NDArray[np.float32], npt.NDArray[np.float32]]:
_validate_center_frequencies_ordering(center_frequencies, frequency_hop)

Expand Down Expand Up @@ -239,10 +239,10 @@ def _swept_stfft(


def _prepend_num_samples(
carryover_num_samples: npt.NDArray[np.int32],
num_samples: npt.NDArray[np.int32],
carryover_num_samples: npt.NDArray[np.int64],
num_samples: npt.NDArray[np.int64],
final_step_spans_two_batches: bool,
) -> npt.NDArray[np.int32]:
) -> npt.NDArray[np.int64]:
"""Prepend the number of samples from the final sweep of the previous batch, to the first
sweep of the current batch."""
if final_step_spans_two_batches:
Expand Down Expand Up @@ -278,7 +278,7 @@ def _prepend_iq_data(
def _get_final_sweep(
previous_iq_data: npt.NDArray[np.complex64],
previous_iq_metadata: spectre_server.core.batches.IQMetadata,
) -> tuple[npt.NDArray[np.complex64], npt.NDArray[np.float32], npt.NDArray[np.int32]]:
) -> tuple[npt.NDArray[np.complex64], npt.NDArray[np.float32], npt.NDArray[np.int64]]:
"""Get IQ samples and metadata from the final sweep of the previous batch."""

if (
Expand Down Expand Up @@ -322,7 +322,7 @@ def _reconstruct_initial_sweep(
iq_data: npt.NDArray[np.complex64],
iq_metadata: spectre_server.core.batches.IQMetadata,
) -> tuple[
npt.NDArray[np.complex64], npt.NDArray[np.float32], npt.NDArray[np.int32], int
npt.NDArray[np.complex64], npt.NDArray[np.float32], npt.NDArray[np.int64], int
]:
"""Reconstruct the initial sweep of the current batch, using data from the previous batch.

Expand Down