[FFmpeg-devel] [PATCH 2/3] avutil/timecode: fix av_timecode_get_smpte_from_framenum with 50/60 fps

Marton Balint cus at passwd.hu
Tue Jul 21 00:04:38 EEST 2020


50/60 fps timecode is using the field bit (which is the same as the phase
correction bit) to signal the least significant bit of a 50/60 fps timecode.
See SMPTE ST 12-1:2014 section 12.1.

Let's add support for this by using the recently added av_timecode_get_smpte
function which handles this properly.

This change affects DV and MXF encoder, MXF has no fate for 50/60fps content,
DV does, therefore the changes. It also affects decklink indev.

MediaInfo (a recent version) confirms that half-frame timecode must be
inserted. (although MediaInfo does not seem to check the field flag).
MXFInspect confirms valid timecode insertion to the System Item of MXF files.

Signed-off-by: Marton Balint <cus at passwd.hu>
---
 libavutil/timecode.c               | 15 +--------------
 libavutil/timecode.h               |  7 +++----
 tests/ref/vsynth/vsynth1-dv-hd     |  2 +-
 tests/ref/vsynth/vsynth2-dv-hd     |  2 +-
 tests/ref/vsynth/vsynth3-dv-hd     |  2 +-
 tests/ref/vsynth/vsynth_lena-dv-hd |  2 +-
 6 files changed, 8 insertions(+), 22 deletions(-)

diff --git a/libavutil/timecode.c b/libavutil/timecode.c
index cca53d73c4..cb916970ef 100644
--- a/libavutil/timecode.c
+++ b/libavutil/timecode.c
@@ -65,20 +65,7 @@ uint32_t av_timecode_get_smpte_from_framenum(const AVTimecode *tc, int framenum)
     ss = framenum / fps      % 60;
     mm = framenum / (fps*60) % 60;
     hh = framenum / (fps*3600) % 24;
-    return 0         << 31 | // color frame flag (0: unsync mode, 1: sync mode)
-           drop      << 30 | // drop  frame flag (0: non drop,    1: drop)
-           (ff / 10) << 28 | // tens  of frames
-           (ff % 10) << 24 | // units of frames
-           0         << 23 | // PC (NTSC) or BGF0 (PAL)
-           (ss / 10) << 20 | // tens  of seconds
-           (ss % 10) << 16 | // units of seconds
-           0         << 15 | // BGF0 (NTSC) or BGF2 (PAL)
-           (mm / 10) << 12 | // tens  of minutes
-           (mm % 10) <<  8 | // units of minutes
-           0         <<  7 | // BGF2 (NTSC) or PC (PAL)
-           0         <<  6 | // BGF1
-           (hh / 10) <<  4 | // tens  of hours
-           (hh % 10);        // units of hours
+    return av_timecode_get_smpte(tc->rate, drop, hh, mm, ss, ff);
 }
 
 uint32_t av_timecode_get_smpte(AVRational rate, int drop, int hh, int mm, int ss, int ff)
diff --git a/libavutil/timecode.h b/libavutil/timecode.h
index 5801330921..e54b116e93 100644
--- a/libavutil/timecode.h
+++ b/libavutil/timecode.h
@@ -66,11 +66,11 @@ int av_timecode_adjust_ntsc_framenum2(int framenum, int fps);
  * the format description as follows:
  * bits 0-5:   hours, in BCD(6bits)
  * bits 6:     BGF1
- * bits 7:     BGF2 (NTSC) or PC (PAL)
+ * bits 7:     BGF2 (NTSC) or FIELD (PAL)
  * bits 8-14:  minutes, in BCD(7bits)
  * bits 15:    BGF0 (NTSC) or BGF2 (PAL)
  * bits 16-22: seconds, in BCD(7bits)
- * bits 23:    PC (NTSC) or BGF0 (PAL)
+ * bits 23:    FIELD (NTSC) or BGF0 (PAL)
  * bits 24-29: frames, in BCD(6bits)
  * bits 30:    drop  frame flag (0: non drop,    1: drop)
  * bits 31:    color frame flag (0: unsync mode, 1: sync mode)
@@ -78,8 +78,7 @@ int av_timecode_adjust_ntsc_framenum2(int framenum, int fps);
  * @note Frame number adjustment is automatically done in case of drop timecode,
  *       you do NOT have to call av_timecode_adjust_ntsc_framenum2().
  * @note The frame number is relative to tc->start.
- * @note Color frame (CF), binary group flags (BGF) and biphase mark polarity
- *       correction (PC) bits are set to zero.
+ * @note Color frame (CF) and binary group flags (BGF) bits are set to zero.
  */
 uint32_t av_timecode_get_smpte_from_framenum(const AVTimecode *tc, int framenum);
 
diff --git a/tests/ref/vsynth/vsynth1-dv-hd b/tests/ref/vsynth/vsynth1-dv-hd
index e22f28c704..a93ce50ec0 100644
--- a/tests/ref/vsynth/vsynth1-dv-hd
+++ b/tests/ref/vsynth/vsynth1-dv-hd
@@ -1,4 +1,4 @@
-77f146c73a24495495c649f1e0d26fee *tests/data/fate/vsynth1-dv-hd.dv
+ce9f887af2391edbfcb21675962db54c *tests/data/fate/vsynth1-dv-hd.dv
 14400000 tests/data/fate/vsynth1-dv-hd.dv
 34b78cf725346c7f819c9d6209b8299a *tests/data/fate/vsynth1-dv-hd.out.rawvideo
 stddev:    4.30 PSNR: 35.45 MAXDIFF:   74 bytes:  7603200/  7603200
diff --git a/tests/ref/vsynth/vsynth2-dv-hd b/tests/ref/vsynth/vsynth2-dv-hd
index 5c4ed86fe7..9552c31948 100644
--- a/tests/ref/vsynth/vsynth2-dv-hd
+++ b/tests/ref/vsynth/vsynth2-dv-hd
@@ -1,4 +1,4 @@
-168f80951daf5eeefacac33fd06db87d *tests/data/fate/vsynth2-dv-hd.dv
+c152c7c3f9ef8f404b4bb7a388b947be *tests/data/fate/vsynth2-dv-hd.dv
 14400000 tests/data/fate/vsynth2-dv-hd.dv
 15dbe911532aca81c67bdd2846419027 *tests/data/fate/vsynth2-dv-hd.out.rawvideo
 stddev:    1.75 PSNR: 43.26 MAXDIFF:   34 bytes:  7603200/  7603200
diff --git a/tests/ref/vsynth/vsynth3-dv-hd b/tests/ref/vsynth/vsynth3-dv-hd
index ed94d08155..d0420d6f07 100644
--- a/tests/ref/vsynth/vsynth3-dv-hd
+++ b/tests/ref/vsynth/vsynth3-dv-hd
@@ -1,4 +1,4 @@
-1211b843d8dde81c583023e15beff35a *tests/data/fate/vsynth3-dv-hd.dv
+973b0856d1d94793bd6e8951284e642d *tests/data/fate/vsynth3-dv-hd.dv
 14400000 tests/data/fate/vsynth3-dv-hd.dv
 a038ad7c3c09f776304ef7accdea9c74 *tests/data/fate/vsynth3-dv-hd.out.rawvideo
 stddev:    0.00 PSNR:999.99 MAXDIFF:    0 bytes:    86700/    86700
diff --git a/tests/ref/vsynth/vsynth_lena-dv-hd b/tests/ref/vsynth/vsynth_lena-dv-hd
index 6764f03c35..8b87da40ba 100644
--- a/tests/ref/vsynth/vsynth_lena-dv-hd
+++ b/tests/ref/vsynth/vsynth_lena-dv-hd
@@ -1,4 +1,4 @@
-fa8df53531f9e58f90bc9a33e5c78ca8 *tests/data/fate/vsynth_lena-dv-hd.dv
+30652b3740a32fa8bcee3b06a66b1dd2 *tests/data/fate/vsynth_lena-dv-hd.dv
 14400000 tests/data/fate/vsynth_lena-dv-hd.dv
 4db4175c80ea1f16b7ec303611b8873a *tests/data/fate/vsynth_lena-dv-hd.out.rawvideo
 stddev:    1.49 PSNR: 44.66 MAXDIFF:   27 bytes:  7603200/  7603200
-- 
2.26.2



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