On 4/8/16, Tobias Rapp <t.r...@noa-archive.com> wrote:
> Add a filter to scan the top lines of video frames for vertical interval
> timecode (VITC) information and attach it as metadata keys.
>
> Signed-off-by: Tobias Rapp <t.r...@noa-archive.com>
> ---
> Changelog | 1 +
> MAINTAINERS | 1 +
> doc/filters.texi | 26 +++++
> libavfilter/Makefile | 1 +
> libavfilter/allfilters.c | 1 +
> libavfilter/version.h | 4 +-
> libavfilter/vf_readvitc.c | 249
> ++++++++++++++++++++++++++++++++++++++++++++++
> 7 files changed, 281 insertions(+), 2 deletions(-)
> create mode 100644 libavfilter/vf_readvitc.c
>
> diff --git a/Changelog b/Changelog
> index b4a4dd7..51613d6 100644
> --- a/Changelog
> +++ b/Changelog
> @@ -22,6 +22,7 @@ version <next>:
> - musx demuxer
> - aix demuxer
> - remap filter
> +- readvitc filter
>
> version 3.0:
> - Common Encryption (CENC) MP4 encoding and decoding support
> diff --git a/MAINTAINERS b/MAINTAINERS
> index a993a67..d2593e5 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -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
> diff --git a/doc/filters.texi b/doc/filters.texi
> index e848584..12a902e 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -10430,6 +10430,32 @@ 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 smaller 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 larger than @code{thr_b}.
> +@end table
> +
> @section remap
>
> Remap pixels using 2nd: Xmap and 3rd: Ymap input video stream.
> diff --git a/libavfilter/Makefile b/libavfilter/Makefile
> index 3a3de48..0994d46 100644
> --- a/libavfilter/Makefile
> +++ b/libavfilter/Makefile
> @@ -223,6 +223,7 @@ 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
> diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
> index b6f4a2c..d59b2d8 100644
> --- a/libavfilter/allfilters.c
> +++ b/libavfilter/allfilters.c
> @@ -243,6 +243,7 @@ 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);
> diff --git a/libavfilter/version.h b/libavfilter/version.h
> index 4cb5a2e..48b9d9a 100644
> --- a/libavfilter/version.h
> +++ b/libavfilter/version.h
> @@ -30,8 +30,8 @@
> #include "libavutil/version.h"
>
> #define LIBAVFILTER_VERSION_MAJOR 6
> -#define LIBAVFILTER_VERSION_MINOR 41
> -#define LIBAVFILTER_VERSION_MICRO 101
> +#define LIBAVFILTER_VERSION_MINOR 42
> +#define LIBAVFILTER_VERSION_MICRO 100
>
> #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
> LIBAVFILTER_VERSION_MINOR, \
> diff --git a/libavfilter/vf_readvitc.c b/libavfilter/vf_readvitc.c
> new file mode 100644
> index 0000000..9bb7220
> --- /dev/null
> +++ b/libavfilter/vf_readvitc.c
> @@ -0,0 +1,249 @@
> +/*
> + * 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/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 '%d' is higher
> than white color threshold '%d'\n",
> + s->threshold_black, s->threshold_white);
> + 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_eq[] = {
> + AV_PIX_FMT_GRAY8,
> + AV_PIX_FMT_YUV410P,
> + AV_PIX_FMT_YUV411P,
> + AV_PIX_FMT_YUV420P,
> + AV_PIX_FMT_YUV422P,
> + AV_PIX_FMT_YUV444P,
AV_PIX_FMT_YUV440P? Also J variants...
> + AV_PIX_FMT_NONE
> + };
> + AVFilterFormats *fmts_list = ff_make_format_list(pixel_fmts_eq);
> + 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);
> +}
> +
> +#if CONFIG_READVITC_FILTER
Not needed.
> +
> +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,
> +};
> +
> +#endif /* CONFIG_READVITC_FILTER */
Not needed.
> --
> 1.9.1
>
>
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>
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