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Fix pts <-> seconds conversions #682

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Merged
merged 2 commits into from
May 15, 2025
Merged

Fix pts <-> seconds conversions #682

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a4a034a
Fix pts <-> seconds conversions
NicolasHug May 15, 2025
06cd220
Fix compile issue
NicolasHug May 15, 2025
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12 changes: 5 additions & 7 deletions src/torchcodec/_core/SingleStreamDecoder.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -17,16 +17,13 @@
namespace facebook::torchcodec {
namespace {

double ptsToSeconds(int64_t pts, int den) {
return static_cast<double>(pts) / den;
}

double ptsToSeconds(int64_t pts, const AVRational& timeBase) {
return ptsToSeconds(pts, timeBase.den);
return static_cast<double>(pts) * timeBase.num / timeBase.den;
}

int64_t secondsToClosestPts(double seconds, const AVRational& timeBase) {
return static_cast<int64_t>(std::round(seconds * timeBase.den));
return static_cast<int64_t>(
std::round(seconds * timeBase.den / timeBase.num));
}

} // namespace
Expand Down Expand Up @@ -151,8 +148,9 @@ void SingleStreamDecoder::initializeDecoder() {
}

if (formatContext_->duration > 0) {
AVRational defaultTimeBase{1, AV_TIME_BASE};
containerMetadata_.durationSeconds =
ptsToSeconds(formatContext_->duration, AV_TIME_BASE);
ptsToSeconds(formatContext_->duration, defaultTimeBase);
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Drive-by: I've been annoyed by the existence of double ptsToSeconds(int64_t pts, int den), so I'm removing it.

defaultTimeBase corresponds to FFmpeg's AV_TIME_BASE_Q, which we can't use due to a C++ pendantic compilation error.

}

if (formatContext_->bit_rate > 0) {
Expand Down
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