>From 36cc44569a898c8401944bc16b791632fd4ac985 Mon Sep 17 00:00:00 2001 From: Dave Rice Date: Mon, 30 Jun 2025 00:00:00 +0200 Subject: [PATCH 4/7] 32-bit timecode to 64-bit RFC 5484 timecode functions --- libavutil/timecode.c | 104 +++++++++++++++++++++++++++++++++++++++++++ libavutil/timecode.h | 22 +++++++++ 2 files changed, 126 insertions(+) diff --git a/libavutil/timecode.c b/libavutil/timecode.c index bca16b6ac2..81fb66a5e4 100644 --- a/libavutil/timecode.c +++ b/libavutil/timecode.c @@ -243,3 +243,107 @@ int av_timecode_init_from_string(AVTimecode *tc, AVRational rate, const char *st return av_timecode_init_from_components(tc, rate, flags, hh, mm, ss, ff, log_ctx); } + +static int bcd_to_int(int bcd) { + return ((bcd >> 4) & 0xF) * 10 + (bcd & 0xF); +} + +uint64_t av_timecode_expand_to_64bit(uint32_t tc32) +{ + uint64_t tc64 = 0; + + int hours_bcd = tc32 & 0x3F; // bits 0-5 + int bgf1 = (tc32 >> 6) & 0x1; // bit 6 + int bgf2 = (tc32 >> 7) & 0x1; // bit 7 + int minutes_bcd = (tc32 >> 8) & 0x7F; // bits 8-14 + int bgf0 = (tc32 >> 15) & 0x1; // bit 15 + int seconds_bcd = (tc32 >> 16) & 0x7F; // bits 16-22 + int frames_bcd = (tc32 >> 24) & 0x3F; // bits 24-29 + int drop = (tc32 >> 30) & 0x1; // bit 30 + int color = (tc32 >> 31) & 0x1; // bit 31 + + int hours = bcd_to_int(hours_bcd); + int minutes = bcd_to_int(minutes_bcd); + int seconds = bcd_to_int(seconds_bcd); + int frames = bcd_to_int(frames_bcd); + + // Units and tens + int uh = hours % 10, th = hours / 10; + int um = minutes % 10, tm = minutes / 10; + int us = seconds % 10, ts = seconds / 10; + int uf = frames % 10, tf = frames / 10; + + // Assign bits as per RFC 5484 layout + tc64 |= (uint64_t)(uf & 0xF) << 0; // Units of frames + tc64 |= 0 << 4; // First binary group + tc64 |= (uint64_t)(tf & 0x3) << 8; // Tens of frames (2 bits) + tc64 |= (uint64_t)drop << 10; // Drop frame flag + tc64 |= (uint64_t)color << 11; // Color frame flag + tc64 |= 0 << 12; // Second binary group + + tc64 |= (uint64_t)(us & 0xF) << 16; // Units of seconds + tc64 |= 0 << 20; // Third binary group + tc64 |= (uint64_t)(ts & 0x7) << 24; // Tens of seconds + tc64 |= 0 << 27; // Polarity correction + tc64 |= 0 << 28; // Fourth binary group + + tc64 |= (uint64_t)(um & 0xF) << 32; // Units of minutes + tc64 |= (uint64_t)0 << 36; // Fifth binary group + tc64 |= (uint64_t)(tm & 0x7) << 40; // Tens of minutes + tc64 |= (uint64_t)bgf0 << 43; // BGF0 + tc64 |= (uint64_t)0 << 44; // Sixth binary group + + tc64 |= (uint64_t)(uh & 0xF) << 48; // Units of hours + tc64 |= (uint64_t)0 << 52; // Seventh binary group + tc64 |= (uint64_t)(th & 0x3) << 56; // Tens of hours + tc64 |= (uint64_t)bgf1 << 58; // BGF1 + tc64 |= (uint64_t)bgf2 << 59; // BGF2 + tc64 |= (uint64_t)0 << 60; // Eighth binary group + + return tc64; +} + +static int int_to_bcd(int val) { + return ((val / 10) << 4) | (val % 10); +} + +uint32_t av_timecode_parse_from_64bit(uint64_t tc64) +{ + uint32_t tc32 = 0; + + int uf = (tc64 >> 0) & 0xF; // Ones of frames + int tf = (tc64 >> 8) & 0x3; // Tens of frames + int drop = (tc64 >> 10) & 0x1; + int color= (tc64 >> 11) & 0x1; + + int us = (tc64 >> 16) & 0xF; // Ones of seconds + int ts = (tc64 >> 24) & 0x7; // Tens of seconds + + int um = (tc64 >> 32) & 0xF; // Ones of minutes + int tm = (tc64 >> 40) & 0x7; // Tens of minutes + int bgf0 = (tc64 >> 43) & 0x1; + + int uh = (tc64 >> 48) & 0xF; // Ones of hours + int th = (tc64 >> 56) & 0x3; // Tens of hours + int bgf1 = (tc64 >> 58) & 0x1; + int bgf2 = (tc64 >> 59) & 0x1; + + int hours = int_to_bcd(th * 10 + uh); + int minutes = int_to_bcd(tm * 10 + um); + int seconds = int_to_bcd(ts * 10 + us); + int frames = int_to_bcd(tf * 10 + uf); + + // Assemble tc32 using the FFmpeg SMPTE 32-bit format + tc32 |= (hours & 0x3F) << 0; // bits 0-5: hours (BCD) + tc32 |= (bgf1 & 0x1) << 6; // bit 6: BGF1 + tc32 |= (bgf2 & 0x1) << 7; // bit 7: BGF2 (or FIELD) + tc32 |= (minutes & 0x7F) << 8; // bits 8-14: minutes (BCD) + tc32 |= (bgf0 & 0x1) << 15; // bit 15: BGF0 + tc32 |= (seconds & 0x7F) << 16; // bits 16-22: seconds (BCD) + tc32 |= 0 << 23; // bit 23: FIELD (set to 0) + tc32 |= (frames & 0x3F) << 24; // bits 24-29: frames (BCD) + tc32 |= (drop & 0x1) << 30; // bit 30: drop frame flag + tc32 |= (color & 0x1) << 31; // bit 31: color frame flag + + return tc32; +} diff --git a/libavutil/timecode.h b/libavutil/timecode.h index fe0fc83576..81713a9adf 100644 --- a/libavutil/timecode.h +++ b/libavutil/timecode.h @@ -196,4 +196,26 @@ int av_timecode_init_from_string(AVTimecode *tc, AVRational rate, const char *st */ int av_timecode_check_frame_rate(AVRational rate); +/** + * Convert a 32-bit SMPTE 12M timecode to 64-bit SMPTE 12M/RFC 5484 format. + * + * This maps the timecode as described in RFC 5484 Section 6.2, + * expanding BCD-encoded time values into bit fields without the sync word. + * + * @param tc32 The 32-bit SMPTE timecode (from DeckLink or av_timecode_get_smpte) + * @return The 64-bit SMPTE 12M timecode format (without sync word) + */ +uint64_t av_timecode_expand_to_64bit(uint32_t tc32); + +/** + * Convert a 64-bit SMPTE 12M/RFC 5484 timecode to 32-bit SMPTE format. + * + * This reconstructs the packed 32-bit SMPTE timecode (DeckLink-style or FFmpeg output) + * from a full 64-bit representation. + * + * @param tc64 The 64-bit timecode value in RFC 5484 / SMPTE 12M format (without sync word) + * @return A 32-bit SMPTE timecode + */ +uint32_t av_timecode_parse_from_64bit(uint64_t tc64); + #endif /* AVUTIL_TIMECODE_H */ -- 2.46.0.windows.1 _______________________________________________ ffmpeg-devel mailing list -- ffmpeg-devel@ffmpeg.org To unsubscribe send an email to ffmpeg-devel-leave@ffmpeg.org