timecode: introduce timecode and honor it in MPEG-1/2.

This is based on the original work by Baptiste Coudurier.

libavcodec/Makefile

@@ -260,6 +260,7 @@ OBJS-$(CONFIG_MPEG_XVMC_DECODER)       += mpegvideo_xvmc.o
 OBJS-$(CONFIG_MPEG1VIDEO_DECODER)      += mpeg12.o mpeg12data.o \
                                           mpegvideo.o error_resilience.o
 OBJS-$(CONFIG_MPEG1VIDEO_ENCODER)      += mpeg12enc.o mpegvideo_enc.o \
+                                          timecode.o                  \
                                           motion_est.o ratecontrol.o  \
                                           mpeg12.o mpeg12data.o       \
                                           mpegvideo.o error_resilience.o
@@ -268,6 +269,7 @@ OBJS-$(CONFIG_MPEG2_VAAPI_HWACCEL)     += vaapi_mpeg2.o
 OBJS-$(CONFIG_MPEG2VIDEO_DECODER)      += mpeg12.o mpeg12data.o \
                                           mpegvideo.o error_resilience.o
 OBJS-$(CONFIG_MPEG2VIDEO_ENCODER)      += mpeg12enc.o mpegvideo_enc.o \
+                                          timecode.o                  \
                                           motion_est.o ratecontrol.o  \
                                           mpeg12.o mpeg12data.o       \
                                           mpegvideo.o error_resilience.o

libavcodec/arm/asm-offsets.h

@@ -29,11 +29,11 @@
 #endif
 
 /* MpegEncContext */
-#define Y_DC_SCALE               0xa8
-#define C_DC_SCALE               0xac
-#define AC_PRED                  0xb0
-#define BLOCK_LAST_INDEX         0xb4
-#define H263_AIC                 0xe4
-#define INTER_SCANTAB_RASTER_END 0x12c
+#define Y_DC_SCALE               0xac
+#define C_DC_SCALE               0xb0
+#define AC_PRED                  0xb4
+#define BLOCK_LAST_INDEX         0xb8
+#define H263_AIC                 0xe8
+#define INTER_SCANTAB_RASTER_END 0x130
 
 #endif /* AVCODEC_ARM_ASM_OFFSETS_H */

libavcodec/mpeg12enc.c

@@ -32,6 +32,8 @@
 #include "mpeg12.h"
 #include "mpeg12data.h"
 #include "bytestream.h"
+#include "timecode.h"
+#include "libavutil/opt.h"
 
 
 static const uint8_t inv_non_linear_qscale[13] = {
@@ -172,11 +174,18 @@ static av_cold int encode_init(AVCodecContext *avctx)
         }
     }
 
+    s->tc.drop = !!(avctx->flags2 & CODEC_FLAG2_DROP_FRAME_TIMECODE);
     if((avctx->flags2 & CODEC_FLAG2_DROP_FRAME_TIMECODE) && s->frame_rate_index != 4){
         av_log(avctx, AV_LOG_ERROR, "Drop frame time code only allowed with 1001/30000 fps\n");
         return -1;
     }
 
+    if (s->tc.str) {
+        s->tc.rate = ff_frame_rate_tab[s->frame_rate_index];
+        if (ff_init_smtpe_timecode(s, &s->tc) < 0)
+            return -1;
+        s->avctx->timecode_frame_start = s->tc.start;
+    }
     return 0;
 }
 
@@ -283,14 +292,14 @@ static void mpeg1_encode_sequence_header(MpegEncContext *s)
             }
 
             put_header(s, GOP_START_CODE);
-            put_bits(&s->pb, 1, !!(s->avctx->flags2 & CODEC_FLAG2_DROP_FRAME_TIMECODE)); /* drop frame flag */
+            put_bits(&s->pb, 1, s->tc.drop);
             /* time code : we must convert from the real frame rate to a
                fake mpeg frame rate in case of low frame rate */
             fps = (framerate.num + framerate.den/2)/ framerate.den;
             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->avctx->flags2 & CODEC_FLAG2_DROP_FRAME_TIMECODE) {
+            if (s->tc.drop) {
                 /* only works for NTSC 29.97 */
                 int d = time_code / 17982;
                 int m = time_code % 17982;
@@ -925,6 +934,17 @@ static void mpeg1_encode_block(MpegEncContext *s,
     put_bits(&s->pb, table_vlc[112][1], table_vlc[112][0]);
 }
 
+static const AVClass class = {
+    .class_name = "mpegvideo",
+    .item_name  = av_default_item_name,
+    .version    = LIBAVUTIL_VERSION_INT,
+    .option     = (const AVOption[]){
+        {TIMECODE_OPT(MpegEncContext,
+         AV_OPT_FLAG_ENCODING_PARAM | AV_OPT_FLAG_VIDEO_PARAM)},
+        {NULL}
+    },
+};
+
 AVCodec ff_mpeg1video_encoder = {
     .name           = "mpeg1video",
     .type           = AVMEDIA_TYPE_VIDEO,
@@ -937,6 +957,7 @@ AVCodec ff_mpeg1video_encoder = {
     .pix_fmts= (const enum PixelFormat[]){PIX_FMT_YUV420P, PIX_FMT_NONE},
     .capabilities= CODEC_CAP_DELAY | CODEC_CAP_SLICE_THREADS,
     .long_name= NULL_IF_CONFIG_SMALL("MPEG-1 video"),
+    .priv_class = &class,
 };
 
 AVCodec ff_mpeg2video_encoder = {
@@ -951,4 +972,5 @@ AVCodec ff_mpeg2video_encoder = {
     .pix_fmts= (const enum PixelFormat[]){PIX_FMT_YUV420P, PIX_FMT_YUV422P, PIX_FMT_NONE},
     .capabilities= CODEC_CAP_DELAY | CODEC_CAP_SLICE_THREADS,
     .long_name= NULL_IF_CONFIG_SMALL("MPEG-2 video"),
+    .priv_class = &class,
 };

libavcodec/mpegvideo.h

@@ -36,6 +36,7 @@
 #include "parser.h"
 #include "mpeg12data.h"
 #include "rl.h"
+#include "timecode.h"
 
 #define FRAME_SKIPPED 100 ///< return value for header parsers if frame is not coded
 
@@ -199,6 +200,7 @@ typedef struct MotionEstContext{
  * MpegEncContext.
  */
 typedef struct MpegEncContext {
+    AVClass *av_class;
     struct AVCodecContext *avctx;
     /* the following parameters must be initialized before encoding */
     int width, height;///< picture size. must be a multiple of 16
@@ -647,6 +649,8 @@ typedef struct MpegEncContext {
     /* RTP specific */
     int rtp_mode;
 
+    struct ff_timecode tc;
+
     uint8_t *ptr_lastgob;
     int swap_uv;             //vcr2 codec is an MPEG-2 variant with U and V swapped
     DCTELEM (*pblocks[12])[64];

libavcodec/timecode.c

@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2006 Smartjog S.A.S, Baptiste Coudurier <baptiste.coudurier@gmail.com>
+ * Copyright (C) 2011 Smartjog S.A.S, Clément Bœsch      <clement.boesch@smartjog.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation;
+ * version 2 of the License.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+*/
+
+/**
+ * @file
+ * Timecode helpers
+ */
+
+#include <stdio.h>
+#include "timecode.h"
+#include "libavutil/log.h"
+
+int ff_init_smtpe_timecode(void *avcl, struct ff_timecode *tc)
+{
+    int hh, mm, ss, ff, fps;
+    char c;
+
+    if (sscanf(tc->str, "%d:%d:%d%c%d", &hh, &mm, &ss, &c, &ff) != 5) {
+        av_log(avcl, AV_LOG_ERROR, "unable to parse timecode, "
+                                   "syntax: hh:mm:ss[:;.]ff\n");
+        return -1;
+    }
+
+    fps       = (tc->rate.num + tc->rate.den/2) / tc->rate.den;
+    tc->start = (hh*3600 + mm*60 + ss) * fps + ff;
+    tc->drop  = c != ':'; // drop if ';', '.', ...
+
+    if (tc->drop) { /* adjust frame number */
+        int tmins = 60*hh + mm;
+        if (tc->rate.den != 1001 || fps != 30) {
+            av_log(avcl, AV_LOG_ERROR, "error: drop frame is only allowed with"
+                                       "30000/1001 FPS");
+            return -2;
+        }
+        tc->start -= 2 * (tmins - tmins/10);
+    }
+    return 0;
+}

libavcodec/timecode.h

@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2006 Smartjog S.A.S, Baptiste Coudurier <baptiste.coudurier@gmail.com>
+ * Copyright (C) 2011 Smartjog S.A.S, Clément Bœsch      <clement.boesch@smartjog.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation;
+ * version 2 of the License.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * Timecode helpers header
+ */
+
+#ifndef AVCODEC_TIMECODE_H
+#define AVCODEC_TIMECODE_H
+
+#include <stdint.h>
+#include "libavutil/rational.h"
+
+#define TIMECODE_OPT(ctx, flags)                                         \
+    "timecode", "set timecode value following hh:mm:ss[:;.]ff format, "  \
+                "use ';' or '.' before frame number for drop frame",     \
+    offsetof(ctx, tc.str),                                               \
+    FF_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, flags
+
+struct ff_timecode {
+    char *str;       ///< string following the hh:mm:ss[:;.]ff format
+    int start;       ///< timecode frame start
+    int drop;        ///< drop flag (1 if drop, else 0)
+    AVRational rate; ///< Frame rate in rationnal form
+};
+
+/**
+ * Parse SMTPE 12M time representation (hh:mm:ss[:;.]ff). str and rate fields
+ * from tc struct must be set.
+ *
+ * @param avcl A pointer to an arbitrary struct of which the first field is a
+ *             pointer to an AVClass struct (used for av_log).
+ * @param tc   Timecode struct pointer
+ * @return     0 on success, negative value on failure
+ * @warning    Adjustement is only valid in NTSC 29.97
+ */
+int ff_init_smtpe_timecode(void *avcl, struct ff_timecode *tc);
+
+#endif /* AVCODEC_TIMECODE_H */