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Add 1s to each timestamp and drop negatives. #26

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Add 1s to each timestamp and drop negatives. #26

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24 changes: 20 additions & 4 deletions src/moq-output.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -156,9 +156,17 @@ void MoQOutput::AudioData(struct encoder_packet *packet)
return;
}

auto pts = util_mul_div64(packet->pts, 1000000ULL * packet->timebase_num, packet->timebase_den);
// Add ~1 second offset to handle negative PTS from audio priming frames.
// TODO: This is slightly wrong when den is not evenly divisible by num, but close enough.
int64_t pts = packet->pts + packet->timebase_den / packet->timebase_num;
if (pts < 0) {
LOG_WARNING("Dropping audio frame with negative PTS: %lld", (long long)packet->pts);
return;
}

auto pts_us = util_mul_div64(pts, 1000000ULL * packet->timebase_num, packet->timebase_den);

auto result = moq_publish_media_frame(audio, packet->data, packet->size, pts);
auto result = moq_publish_media_frame(audio, packet->data, packet->size, pts_us);
Comment on lines +159 to +169
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@coderabbitai coderabbitai bot Jan 22, 2026

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⚠️ Potential issue | 🟡 Minor

Guard against potential division by zero.

The calculation packet->timebase_den / packet->timebase_num on line 161 will cause undefined behavior if timebase_num is ever 0. While valid encoder packets should always have a non-zero timebase numerator, adding a defensive check would improve robustness.

🛡️ Suggested defensive guard 
 	// Add ~1 second offset to handle negative PTS from audio priming frames.
 	// TODO: This is slightly wrong when den is not evenly divisible by num, but close enough.
+	if (packet->timebase_num == 0) {
+		LOG_WARNING("Invalid audio timebase (num=0), dropping frame");
+		return;
+	}
 	int64_t pts = packet->pts + packet->timebase_den / packet->timebase_num;
🤖 Prompt for AI Agents 
In `@src/moq-output.cpp` around lines 159 - 169, The pts calculation uses
packet->timebase_den / packet->timebase_num which can divide by zero if
packet->timebase_num == 0; add a defensive guard before computing pts (e.g.,
check packet->timebase_num != 0 and packet->timebase_den != 0) and handle the
error path by logging a warning (using LOG_WARNING) and returning early so
util_mul_div64 and moq_publish_media_frame are not called with invalid values;
update the block around the pts calculation that references
packet->timebase_num, packet->timebase_den, pts, util_mul_div64(...) and
moq_publish_media_frame(...) to perform this check.

if (result < 0) {
LOG_ERROR("Failed to write audio frame: %d", result);
return;
Expand All @@ -177,9 +185,17 @@ void MoQOutput::VideoData(struct encoder_packet *packet)
return;
}

auto pts = util_mul_div64(packet->pts, 1000000ULL * packet->timebase_num, packet->timebase_den);
// Add ~1 second offset to match audio for A/V sync.
// TODO: This is slightly wrong when den is not evenly divisible by num, but close enough.
int64_t pts = packet->pts + packet->timebase_den / packet->timebase_num;
if (pts < 0) {
LOG_WARNING("Dropping video frame with negative PTS: %lld", (long long)packet->pts);
return;
}

auto pts_us = util_mul_div64(pts, 1000000ULL * packet->timebase_num, packet->timebase_den);

auto result = moq_publish_media_frame(video, packet->data, packet->size, pts);
auto result = moq_publish_media_frame(video, packet->data, packet->size, pts_us);
if (result < 0) {
LOG_ERROR("Failed to write video frame: %d", result);
return;
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