[FFmpeg-devel] [PATCH 3/8] timecode: move dropframe code and doxycomment it.
Clément Bœsch
ubitux at gmail.com
Wed Jul 27 18:45:13 CEST 2011
From: Clément Bœsch <clement.boesch at smartjog.com>
This is based on the original work by Baptiste Coudurier.
---
libavcodec/mpeg12enc.c | 9 ++-------
libavcodec/timecode.c | 9 +++++++++
libavcodec/timecode.h | 8 ++++++++
3 files changed, 19 insertions(+), 7 deletions(-)
diff --git a/libavcodec/mpeg12enc.c b/libavcodec/mpeg12enc.c
index 021f35e..719bd6b 100644
--- a/libavcodec/mpeg12enc.c
+++ b/libavcodec/mpeg12enc.c
@@ -299,13 +299,8 @@ static void mpeg1_encode_sequence_header(MpegEncContext *s)
time_code = s->current_picture_ptr->f.coded_picture_number + s->avctx->timecode_frame_start;
s->gop_picture_number = s->current_picture_ptr->f.coded_picture_number;
- if (s->tc.drop) {
- /* only works for NTSC 29.97 */
- int d = time_code / 17982;
- int m = time_code % 17982;
- //if (m < 2) m += 2; /* not needed since -2,-1 / 1798 in C returns 0 */
- time_code += 18 * d + 2 * ((m - 2) / 1798);
- }
+ if (s->tc.drop)
+ time_code = ff_framenum_to_drop_timecode(time_code);
put_bits(&s->pb, 5, (uint32_t)((time_code / (fps * 3600)) % 24));
put_bits(&s->pb, 6, (uint32_t)((time_code / (fps * 60)) % 60));
put_bits(&s->pb, 1, 1);
diff --git a/libavcodec/timecode.c b/libavcodec/timecode.c
index d9c3f7d..434b3cb 100644
--- a/libavcodec/timecode.c
+++ b/libavcodec/timecode.c
@@ -28,6 +28,15 @@
#include "timecode.h"
#include "libavutil/log.h"
+int ff_framenum_to_drop_timecode(int frame_num)
+{
+ /* only works for NTSC 29.97 */
+ int d = frame_num / 17982;
+ int m = frame_num % 17982;
+ //if (m < 2) m += 2; /* not needed since -2,-1 / 1798 in C returns 0 */
+ return frame_num + 18 * d + 2 * ((m - 2) / 1798);
+}
+
int ff_init_smtpe_timecode(void *avcl, struct ff_timecode *tc)
{
int hh, mm, ss, ff, fps;
diff --git a/libavcodec/timecode.h b/libavcodec/timecode.h
index d2f6606..bf4116b 100644
--- a/libavcodec/timecode.h
+++ b/libavcodec/timecode.h
@@ -44,6 +44,14 @@ struct ff_timecode {
};
/**
+ * @brief Adjust frame number for NTSC drop frame time code
+ * @param frame_num Actual frame number to adjust
+ * @return Adjusted frame number
+ * @warning Adjustment is only valid in NTSC 29.97
+ */
+int ff_framenum_to_drop_timecode(int frame_num);
+
+/**
* Parse SMTPE 12M time representation (hh:mm:ss[:;.]ff). str and rate fields
* from tc struct must be set.
*
--
1.7.5.4
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