@@ -25,6 +25,7 @@ version <next>:

 - hash and framehash muxers

 - colorspace filter

 - hdcd filter

+- readvitc filter

 version 3.0:

 - Common Encryption (CENC) MP4 encoding and decoding support

@@ -385,6 +385,7 @@ Filters:

   vf_neighbor.c                         Paul B Mahol

   vf_psnr.c                             Paul B Mahol

   vf_random.c                           Paul B Mahol

+  vf_readvitc.c                         Tobias Rapp (CC t.rapp at noa-archive dot com)

   vf_scale.c                            Michael Niedermayer

   vf_separatefields.c                   Paul B Mahol

   vf_ssim.c                             Paul B Mahol

@@ -10618,6 +10618,43 @@ less than @code{0}, the filter will try to use a good random seed on a

 best effort basis.

 @end table

+@section readvitc

+

+Read vertical interval timecode (VITC) information from the top lines of a

+video frame.

+

+The filter adds frame metadata key @code{lavfi.readvitc.tc_str} with the

+timecode value, if a valid timecode has been detected. Further metadata key

+@code{lavfi.readvitc.found} is set to 0/1 depending on whether

+timecode data has been found or not.

+

+This filter accepts the following options:

+

+@table @option

+@item scan_max

+Set the maximum number of lines to scan for VITC data. If the value is set to

+@code{-1} the full video frame is scanned. Default is @code{45}.

+

+@item thr_b

+Set the luma threshold for black. Accepts float numbers in the range [0.0,1.0],

+default value is @code{0.2}. The value must be equal or less than @code{thr_w}.

+

+@item thr_w

+Set the luma threshold for white. Accepts float numbers in the range [0.0,1.0],

+default value is @code{0.6}. The value must be equal or greater than @code{thr_b}.

+@end table

+

+@subsection Examples

+

+@itemize

+@item

+Detect and draw VITC data onto the video frame; if no valid VITC is detected,

+draw @code{--:--:--:--} as a placeholder:

+@example

+ffmpeg -i input.avi -filter:v 'readvitc,drawtext=fontfile=FreeMono.ttf:text=%@{metadata\\:lavfi.readvitc.tc_str\\:--\\\\\\:--\\\\\\:--\\\\\\:--@}:x=(w-tw)/2:y=400-ascent'

+@end example

+@end itemize

+

 @section remap

 Remap pixels using 2nd: Xmap and 3rd: Ymap input video stream.

@@ -227,6 +227,7 @@ OBJS-$(CONFIG_PSNR_FILTER)                   += vf_psnr.o dualinput.o framesync.

 OBJS-$(CONFIG_PULLUP_FILTER)                 += vf_pullup.o

 OBJS-$(CONFIG_QP_FILTER)                     += vf_qp.o

 OBJS-$(CONFIG_RANDOM_FILTER)                 += vf_random.o

+OBJS-$(CONFIG_READVITC_FILTER)               += vf_readvitc.o

 OBJS-$(CONFIG_REALTIME_FILTER)               += f_realtime.o

 OBJS-$(CONFIG_REMAP_FILTER)                  += vf_remap.o framesync.o

 OBJS-$(CONFIG_REMOVEGRAIN_FILTER)            += vf_removegrain.o

@@ -247,6 +247,7 @@ void avfilter_register_all(void)

     REGISTER_FILTER(PULLUP,         pullup,         vf);

     REGISTER_FILTER(QP,             qp,             vf);

     REGISTER_FILTER(RANDOM,         random,         vf);

+    REGISTER_FILTER(READVITC,       readvitc,       vf);

     REGISTER_FILTER(REALTIME,       realtime,       vf);

     REGISTER_FILTER(REMAP,          remap,          vf);

     REGISTER_FILTER(REMOVEGRAIN,    removegrain,    vf);

@@ -30,7 +30,7 @@

 #include "libavutil/version.h"

 #define LIBAVFILTER_VERSION_MAJOR   6

-#define LIBAVFILTER_VERSION_MINOR  42

+#define LIBAVFILTER_VERSION_MINOR  43

 #define LIBAVFILTER_VERSION_MICRO 100

 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

new file mode 100644

@@ -0,0 +1,258 @@

+/*

+ * Copyright (c) 2016 Tobias Rapp

+ *

+ * This file is part of FFmpeg.

+ *

+ * FFmpeg is free software; you can redistribute it and/or

+ * modify it under the terms of the GNU Lesser General Public

+ * License as published by the Free Software Foundation; either

+ * version 2.1 of the License, or (at your option) any later version.

+ *

+ * 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

+ * Lesser General Public License for more details.

+ *

+ * You should have received a copy of the GNU Lesser 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

+ * Filter for reading the vertical interval timecode (VITC).

+ * See also https://en.wikipedia.org/wiki/Vertical_interval_timecode

+ */

+

+#include "libavutil/common.h"

+#include "libavutil/internal.h"

+#include "libavutil/opt.h"

+#include "libavutil/pixdesc.h"

+#include "libavutil/timecode.h"

+#include "avfilter.h"

+#include "formats.h"

+#include "internal.h"

+

+#define LINE_DATA_SIZE 9

+

+typedef struct ReadVitcContext {

+    const AVClass *class;

+

+    int scan_max;

+    double thr_b;

+    double thr_w;

+

+    int threshold_black;

+    int threshold_white;

+    int threshold_gray;

+    int grp_width;

+    uint8_t line_data[LINE_DATA_SIZE];

+    char tcbuf[AV_TIMECODE_STR_SIZE];

+} ReadVitcContext;

+

+#define OFFSET(x) offsetof(ReadVitcContext, x)

+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM

+

+static const AVOption readvitc_options[] = {

+    { "scan_max", "maximum line numbers to scan for VITC data", OFFSET(scan_max), AV_OPT_TYPE_INT, {.i64 = 45 }, -1, INT_MAX, FLAGS },

+    { "thr_b",    "black color threshold", OFFSET(thr_b), AV_OPT_TYPE_DOUBLE, {.dbl = 0.2 }, 0, 1.0, FLAGS },

+    { "thr_w",    "white color threshold", OFFSET(thr_w), AV_OPT_TYPE_DOUBLE, {.dbl = 0.6 }, 0, 1.0, FLAGS },

+    { NULL }

+};

+

+AVFILTER_DEFINE_CLASS(readvitc);

+

+static uint8_t get_vitc_crc( uint8_t *line ) {

+    uint8_t crc;

+

+    crc = 0x01 | (line[0] << 2);

+    crc ^= (line[0] >> 6) | 0x04 | (line[1] << 4);

+    crc ^= (line[1] >> 4) | 0x10 | (line[2] << 6);

+    crc ^= (line[2] >> 2) | 0x40;

+    crc ^= line[3];

+    crc ^= 0x01 | (line[4] << 2);

+    crc ^= (line[4] >> 6) | 0x04 | (line[5] << 4);

+    crc ^= (line[5] >> 4) | 0x10 | (line[6] << 6);

+    crc ^= (line[6] >> 2) | 0x40;

+    crc ^= line[7];

+    crc ^= 0x01;

+    crc = (crc >> 2) | (crc << 6);  // rotate byte right by two bits

+    return crc;

+}

+

+static inline uint8_t get_pit_avg3( uint8_t *line, int i ) {

+    return ((line[i-1] + line[i] + line[i+1]) / 3);

+}

+

+static int read_vitc_line( ReadVitcContext *ctx, uint8_t *src, int line_size, int width, int height )

+{

+    uint8_t *scan_line;

+    int grp_index, pit_index;

+    int grp_start_pos;

+    uint8_t pit_value;

+    int x, y, res = 0;

+

+    if (ctx->scan_max >= 0)

+        height = FFMIN(height, ctx->scan_max);

+

+    // scan lines for VITC data, starting from the top

+    for (y = 0; y < height; y++) {

+        scan_line = src;

+        memset(ctx->line_data, 0, LINE_DATA_SIZE);

+        grp_index = 0;

+        x = 0;

+        while ((x < width) && (grp_index < 9)) {

+            // search next sync pattern

+            while ((x < width) && (scan_line[x] < ctx->threshold_white))

+                x++;

+            while ((x < width) && (scan_line[x] > ctx->threshold_black))

+                x++;

+            x = FFMAX(x - ((ctx->grp_width+10) / 20), 1);  // step back a half pit

+            grp_start_pos = x;

+            if ((grp_start_pos + ctx->grp_width) > width)

+                break;  // not enough pixels for reading a whole pit group

+            pit_value = get_pit_avg3(scan_line, x);

+            if (pit_value < ctx->threshold_white)

+               break;  // first sync bit mismatch

+            x = grp_start_pos + ((ctx->grp_width) / 10);

+            pit_value = get_pit_avg3(scan_line, x);

+            if (pit_value > ctx->threshold_black )

+                break;  // second sync bit mismatch

+            for (pit_index = 0; pit_index <= 7; pit_index++) {

+                x = grp_start_pos + (((pit_index+2)*ctx->grp_width) / 10);

+                pit_value = get_pit_avg3(scan_line, x);

+                if (pit_value > ctx->threshold_gray)

+                    ctx->line_data[grp_index] |= (1 << pit_index);

+            }

+            grp_index++;

+        }

+        if ((grp_index == 9) && (get_vitc_crc(ctx->line_data) == ctx->line_data[8])) {

+            res = 1;

+            break;

+        }

+        src += line_size;

+    }

+

+    return res;

+}

+

+static unsigned bcd2uint(uint8_t high, uint8_t low)

+{

+   if (high > 9 || low > 9)

+       return 0;

+   return 10*high + low;

+}

+

+static char *make_vitc_tc_string(char *buf, uint8_t *line)

+{

+    unsigned hh   = bcd2uint(line[7] & 0x03, line[6] & 0x0f);  // 6-bit hours

+    unsigned mm   = bcd2uint(line[5] & 0x07, line[4] & 0x0f);  // 7-bit minutes

+    unsigned ss   = bcd2uint(line[3] & 0x07, line[2] & 0x0f);  // 7-bit seconds

+    unsigned ff   = bcd2uint(line[1] & 0x03, line[0] & 0x0f);  // 6-bit frames

+    unsigned drop = (line[1] & 0x04);                          // 1-bit drop flag

+    snprintf(buf, AV_TIMECODE_STR_SIZE, "%02u:%02u:%02u%c%02u",

+             hh, mm, ss, drop ? ';' : ':', ff);

+    return buf;

+}

+

+static av_cold int init(AVFilterContext *ctx)

+{

+    ReadVitcContext *s = ctx->priv;

+

+    s->threshold_black = s->thr_b * UINT8_MAX;

+    s->threshold_white = s->thr_w * UINT8_MAX;

+    if (s->threshold_black > s->threshold_white) {

+        av_log(ctx, AV_LOG_WARNING, "Black color threshold is higher than white color threshold (%g > %g)\n",

+                s->thr_b, s->thr_w);

+        return AVERROR(EINVAL);

+    }

+    s->threshold_gray = s->threshold_white - ((s->threshold_white - s->threshold_black) / 2);

+    av_log(ctx, AV_LOG_DEBUG, "threshold_black:%d threshold_white:%d threshold_gray:%d\n",

+            s->threshold_black, s->threshold_white, s->threshold_gray);

+

+    return 0;

+}

+

+static int config_props(AVFilterLink *inlink)

+{

+    AVFilterContext *ctx = inlink->dst;

+    ReadVitcContext *s = ctx->priv;

+

+    s->grp_width = inlink->w * 5 / 48;

+    av_log(ctx, AV_LOG_DEBUG, "w:%d h:%d grp_width:%d scan_max:%d\n",

+            inlink->w, inlink->h, s->grp_width, s->scan_max);

+    return 0;

+}

+

+static int query_formats(AVFilterContext *ctx)

+{

+    static const enum AVPixelFormat pixel_fmts[] = {

+        AV_PIX_FMT_GRAY8,

+        AV_PIX_FMT_NV12,

+        AV_PIX_FMT_NV16,

+        AV_PIX_FMT_NV21,

+        AV_PIX_FMT_YUV410P,

+        AV_PIX_FMT_YUV411P,

+        AV_PIX_FMT_YUV420P,

+        AV_PIX_FMT_YUV422P,

+        AV_PIX_FMT_YUV440P,

+        AV_PIX_FMT_YUV444P,

+        AV_PIX_FMT_YUVA420P,

+        AV_PIX_FMT_YUVA422P,

+        AV_PIX_FMT_YUVA444P,

+        AV_PIX_FMT_YUVJ411P,

+        AV_PIX_FMT_YUVJ420P,

+        AV_PIX_FMT_YUVJ422P,

+        AV_PIX_FMT_YUVJ440P,

+        AV_PIX_FMT_YUVJ444P,

+        AV_PIX_FMT_NONE

+    };

+    AVFilterFormats *fmts_list = ff_make_format_list(pixel_fmts);

+    if (!fmts_list)

+        return AVERROR(ENOMEM);

+    return ff_set_common_formats(ctx, fmts_list);

+}

+

+static int filter_frame(AVFilterLink *inlink, AVFrame *frame)

+{

+    AVFilterContext *ctx = inlink->dst;

+    AVFilterLink *outlink = ctx->outputs[0];

+    ReadVitcContext *s = ctx->priv;

+    int found;

+

+    found = read_vitc_line(s, frame->data[0], frame->linesize[0], inlink->w, inlink->h);

+    av_dict_set(&frame->metadata, "lavfi.readvitc.found", (found ? "1" : "0"), 0);

+    if (found)

+        av_dict_set(&frame->metadata, "lavfi.readvitc.tc_str", make_vitc_tc_string(s->tcbuf, s->line_data), 0);

+

+    return ff_filter_frame(outlink, frame);

+}

+

+static const AVFilterPad inputs[] = {

+    {

+        .name         = "default",

+        .type         = AVMEDIA_TYPE_VIDEO,

+        .filter_frame = filter_frame,

+        .config_props = config_props,

+    },

+    { NULL }

+};

+

+static const AVFilterPad outputs[] = {

+    {

+        .name = "default",

+        .type = AVMEDIA_TYPE_VIDEO,

+    },

+    { NULL }

+};

+

+AVFilter ff_vf_readvitc = {

+    .name          = "readvitc",

+    .description   = NULL_IF_CONFIG_SMALL("Read vertical interval timecode and write it to frame metadata."),

+    .priv_size     = sizeof(ReadVitcContext),

+    .priv_class    = &readvitc_class,

+    .inputs        = inputs,

+    .outputs       = outputs,

+    .init          = init,

+    .query_formats = query_formats,

+};