Files
mpd/src/lib/ffmpeg/Time.hxx
2023-03-06 14:59:48 +01:00

96 lines
2.0 KiB
C++

// SPDX-License-Identifier: GPL-2.0-or-later
// Copyright The Music Player Daemon Project
#ifndef MPD_FFMPEG_TIME_HXX
#define MPD_FFMPEG_TIME_HXX
#include "Chrono.hxx"
extern "C" {
#include <libavutil/avutil.h>
#include <libavutil/mathematics.h>
}
#include <cassert>
#include <cstdint>
/* redefine AV_TIME_BASE_Q because libavutil's macro definition is a
compound literal, which is illegal in C++ */
#ifdef AV_TIME_BASE_Q
#undef AV_TIME_BASE_Q
#endif
static constexpr AVRational AV_TIME_BASE_Q{1, AV_TIME_BASE};
/**
* Convert a FFmpeg time stamp to a floating point value (in seconds).
*/
[[gnu::const]]
static inline FloatDuration
FfmpegTimeToDouble(int64_t t, const AVRational time_base) noexcept
{
assert(t != (int64_t)AV_NOPTS_VALUE);
return FloatDuration(av_rescale_q(t, time_base, {1, 1024}))
/ 1024;
}
/**
* Convert a std::ratio to a #AVRational.
*/
template<typename Ratio>
constexpr AVRational
RatioToAVRational()
{
return { Ratio::num, Ratio::den };
}
/**
* Convert a FFmpeg time stamp to a #SongTime.
*/
[[gnu::const]]
static inline SongTime
FromFfmpegTime(int64_t t, const AVRational time_base) noexcept
{
assert(t != (int64_t)AV_NOPTS_VALUE);
return SongTime::FromMS(av_rescale_q(t, time_base,
{1, 1000}));
}
/**
* Convert a FFmpeg time stamp to a #SignedSongTime.
*/
[[gnu::const]]
static inline SignedSongTime
FromFfmpegTimeChecked(int64_t t, const AVRational time_base) noexcept
{
return t != (int64_t)AV_NOPTS_VALUE
? SignedSongTime(FromFfmpegTime(t, time_base))
: SignedSongTime::Negative();
}
/**
* Convert a #SongTime to a FFmpeg time stamp with the given base.
*/
[[gnu::const]]
static inline int64_t
ToFfmpegTime(SongTime t, const AVRational time_base) noexcept
{
return av_rescale_q(t.count(),
RatioToAVRational<SongTime::period>(),
time_base);
}
/**
* Replace #AV_NOPTS_VALUE with the given fallback.
*/
constexpr int64_t
FfmpegTimestampFallback(int64_t t, int64_t fallback)
{
return t != int64_t(AV_NOPTS_VALUE)
? t
: fallback;
}
#endif