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closedcaption: Add new "line 21 VBI" CC decoder

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Allows detecting and extracting CEA608 closed caption present on
the VBI of analog NTSC SD signals.
This commit is contained in:
Edward Hervey 2018-03-19 10:56:31 +01:00 committed by Edward Hervey
parent 9ee58b5aeb
commit 2a1553cb88
4 changed files with 564 additions and 1 deletions
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3
ext/closedcaption/Makefile.am
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@ -21,6 +21,8 @@ libgstclosedcaption_la_SOURCES = \
$(zvbi_headers) \
gstccextractor.c \
gstccextractor.h \
gstline21dec.c \
gstline21dec.h \
gstclosedcaption.c
libgstclosedcaption_la_CFLAGS = \
@ -37,4 +39,5 @@ libgstclosedcaption_la_LDFLAGS = $(GST_PLUGIN_LDFLAGS)
noinst_HEADERS = \
gstccextractor.h \
gstline21dec.h \
$(zvbi_headers)

10
ext/closedcaption/gstclosedcaption.c
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@ -26,12 +26,20 @@
#include <gst/gst.h>
#include "gstccextractor.h"
#include "gstline21dec.h"
static gboolean
closedcaption_init (GstPlugin * ccextractor)
{
return gst_element_register (ccextractor, "ccextractor", GST_RANK_NONE,
gboolean ret;
ret = gst_element_register (ccextractor, "ccextractor", GST_RANK_NONE,
GST_TYPE_CCEXTRACTOR);
ret &= gst_element_register (ccextractor, "line21decoder", GST_RANK_NONE,
GST_TYPE_LINE21DECODER);
return ret;
}
GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,

479
ext/closedcaption/gstline21dec.c Normal file
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@ -0,0 +1,479 @@
/*
* GStreamer
* Copyright (C) 2018 Edward Hervey <edward@centricular.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/**
* SECTION:element-line21decoder
* @title: line21decoder
*
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <gst/gst.h>
#include <gst/video/video.h>
#include <string.h>
#include "gstline21dec.h"
GST_DEBUG_CATEGORY_STATIC (gst_line_21_decoder_debug);
#define GST_CAT_DEFAULT gst_line_21_decoder_debug
enum
{
PROP_0,
};
#define SUPPORTED_FORMATS "{ I420, YUY2, YVYU, UYVY, VYUY, v210 }"
static GstStaticPadTemplate sinktemplate = GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS (GST_VIDEO_CAPS_MAKE (SUPPORTED_FORMATS)));
static GstStaticPadTemplate srctemplate = GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS (GST_VIDEO_CAPS_MAKE (SUPPORTED_FORMATS)));
G_DEFINE_TYPE (GstLine21Decoder, gst_line_21_decoder, GST_TYPE_VIDEO_FILTER);
#define parent_class gst_line_21_decoder_parent_class
static void gst_line_21_decoder_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void gst_line_21_decoder_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static GstStateChangeReturn gst_line_21_decoder_change_state (GstElement *
element, GstStateChange transition);
static void gst_line_21_decoder_finalize (GObject * self);
static gboolean gst_line_21_decoder_set_info (GstVideoFilter * filter,
GstCaps * incaps, GstVideoInfo * in_info,
GstCaps * outcaps, GstVideoInfo * out_info);
static GstFlowReturn gst_line_21_decoder_transform_ip (GstVideoFilter * filter,
GstVideoFrame * frame);
static GstFlowReturn gst_line_21_decoder_prepare_output_buffer (GstBaseTransform
* trans, GstBuffer * in, GstBuffer ** out);
static void
gst_line_21_decoder_class_init (GstLine21DecoderClass * klass)
{
GObjectClass *gobject_class;
GstElementClass *gstelement_class;
GstBaseTransformClass *transform_class;
GstVideoFilterClass *filter_class;
gobject_class = (GObjectClass *) klass;
gstelement_class = (GstElementClass *) klass;
transform_class = (GstBaseTransformClass *) klass;
filter_class = (GstVideoFilterClass *) klass;
gobject_class->set_property = gst_line_21_decoder_set_property;
gobject_class->get_property = gst_line_21_decoder_get_property;
gobject_class->finalize = gst_line_21_decoder_finalize;
gstelement_class->change_state =
GST_DEBUG_FUNCPTR (gst_line_21_decoder_change_state);
gst_element_class_set_static_metadata (gstelement_class,
"Line 21 CC Decoder",
"Filter",
"Extract line21 CC from SD video streams",
"Edward Hervey <edward@centricular.com>");
gst_element_class_add_static_pad_template (gstelement_class, &sinktemplate);
gst_element_class_add_static_pad_template (gstelement_class, &srctemplate);
transform_class->prepare_output_buffer =
gst_line_21_decoder_prepare_output_buffer;
filter_class->set_info = gst_line_21_decoder_set_info;
filter_class->transform_frame_ip = gst_line_21_decoder_transform_ip;
GST_DEBUG_CATEGORY_INIT (gst_line_21_decoder_debug, "line21decoder",
0, "Line 21 CC Decoder");
vbi_initialize_gst_debug ();
}
static void
gst_line_21_decoder_reset (GstLine21Decoder * self)
{
self->line21_offset = -1;
self->max_line_probes = 40;
if (self->info) {
gst_video_info_free (self->info);
self->info = NULL;
}
g_free (self->converted_lines);
self->converted_lines = NULL;
}
static void
gst_line_21_decoder_init (GstLine21Decoder * filter)
{
gst_line_21_decoder_reset (filter);
}
static void
gst_line_21_decoder_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
/* GstLine21Decoder *filter = GST_LINE21DECODER (object); */
switch (prop_id) {
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_line_21_decoder_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec)
{
/* GstLine21Decoder *filter = GST_LINE21DECODER (object); */
switch (prop_id) {
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static vbi_pixfmt
vbi_pixfmt_from_gst_video_format (GstVideoFormat format,
gboolean * convert_v210)
{
*convert_v210 = FALSE;
switch (format) {
case GST_VIDEO_FORMAT_I420:
return VBI_PIXFMT_YUV420;
case GST_VIDEO_FORMAT_YUY2:
return VBI_PIXFMT_YUYV;
case GST_VIDEO_FORMAT_YVYU:
return VBI_PIXFMT_YVYU;
case GST_VIDEO_FORMAT_UYVY:
return VBI_PIXFMT_UYVY;
case GST_VIDEO_FORMAT_VYUY:
return VBI_PIXFMT_VYUY;
/* for v210 we'll convert it to I420 luma */
case GST_VIDEO_FORMAT_v210:
*convert_v210 = TRUE;
return VBI_PIXFMT_YUV420;
/* All the other formats are not really bullet-proof. Force conversion */
default:
return 0;
}
#undef NATIVE_VBI_FMT
}
static gboolean
gst_line_21_decoder_set_info (GstVideoFilter * filter,
GstCaps * incaps, GstVideoInfo * in_info,
GstCaps * outcaps, GstVideoInfo * out_info)
{
GstLine21Decoder *self = (GstLine21Decoder *) filter;
vbi_pixfmt fmt =
vbi_pixfmt_from_gst_video_format (GST_VIDEO_INFO_FORMAT (in_info),
&self->convert_v210);
GST_DEBUG_OBJECT (filter, "caps %" GST_PTR_FORMAT, incaps);
GST_DEBUG_OBJECT (filter, "plane_stride:%u , comp_stride:%u , pstride:%u",
GST_VIDEO_INFO_PLANE_STRIDE (in_info, 0),
GST_VIDEO_INFO_COMP_STRIDE (in_info, 0),
GST_VIDEO_INFO_COMP_PSTRIDE (in_info, 0));
GST_DEBUG_OBJECT (filter, "#planes : %d #components : %d",
GST_VIDEO_INFO_N_PLANES (in_info), GST_VIDEO_INFO_N_COMPONENTS (in_info));
if (GST_VIDEO_INFO_WIDTH (in_info) != 720) {
GST_DEBUG_OBJECT (filter, "Only 720 pixel wide formats are supported");
self->compatible_format = FALSE;
return TRUE;
}
if (fmt == 0) {
if (GST_VIDEO_INFO_FORMAT (in_info) == GST_VIDEO_FORMAT_v210) {
GST_DEBUG_OBJECT (filter,
"Format not supported natively, Adding conversion to YUY2");
self->compatible_format = TRUE;
self->convert_v210 = TRUE;
} else {
GST_DEBUG_OBJECT (filter, "Unsupported format");
self->compatible_format = FALSE;
}
return TRUE;
}
if (GST_VIDEO_INFO_WIDTH (in_info) == 720
&& GST_VIDEO_INFO_HEIGHT (in_info) >= 200) {
GST_DEBUG_OBJECT (filter, "Compatible size!");
GST_DEBUG_OBJECT (filter,
"Compatible format plane_stride:%u , comp_stride:%u , pstride:%u",
GST_VIDEO_INFO_PLANE_STRIDE (in_info, 0),
GST_VIDEO_INFO_COMP_STRIDE (in_info, 0),
GST_VIDEO_INFO_COMP_PSTRIDE (in_info, 0));
self->compatible_format = TRUE;
if (self->convert_v210) {
self->info = gst_video_info_new ();
gst_video_info_set_format (self->info, GST_VIDEO_FORMAT_I420,
GST_VIDEO_INFO_WIDTH (in_info), GST_VIDEO_INFO_HEIGHT (in_info));
/* Allocate space for two *I420* Y lines (with stride) */
self->converted_lines =
g_malloc0 (2 * GST_VIDEO_INFO_COMP_STRIDE (self->info, 0));
} else
self->info = gst_video_info_copy (in_info);
/* initialize the decoder */
vbi_raw_decoder_init (&self->zvbi_decoder);
/* We either deal with PAL (625 lines) or NTSC (525 lines) */
self->zvbi_decoder.scanning = 525;
/* The pixel format. Quite a few formats are handled by zvbi, but
* some are not and require conversion (or cheating) */
self->zvbi_decoder.sampling_format = fmt;
/* Sampling rate. For BT.601 it's 13.5MHz */
self->zvbi_decoder.sampling_rate = 13.5e6; /* Hz (i.e. BT.601) */
/* Stride */
self->zvbi_decoder.bytes_per_line =
GST_VIDEO_INFO_COMP_STRIDE (self->info, 0);
/* Sampling starts 9.7 µs from the front edge of the
hor. sync pulse. You may have to adjust this.
NOTE : This is actually ignored in the code ...
*/
self->zvbi_decoder.offset = 9.7e-6 * 13.5e6;
/* The following values indicate what we are feeding to zvbi.
* By setting start[0] = 21, we are telling zvbi that the very
* beginning of the data we are feeding to it corresponds to
* line 21 (which is where CC1/CC3 is located).
*
* Then by specifying count[0] = 1, we are telling it to only
* scan 1 line from the beginning of the data.
*
* It is more efficient and flexible to do it this way, since
* we can then control what we are feeding it (i.e. *we* will
* figure out the offset to line 21, which might or might not
* be the beginning of the buffer data, and feed data from
* there). This would also allows us to have a "scanning" mode
* where we repeatedly provide it with pairs of lines until it
* finds something. */
self->zvbi_decoder.start[0] = 21;
self->zvbi_decoder.count[0] = 1;
/* Second field. */
self->zvbi_decoder.start[1] = 284;
self->zvbi_decoder.count[1] = 1;
/* FIXME : Adjust according to the info.interlace_mode ! */
self->zvbi_decoder.interlaced = TRUE;
/* synchronous is essentially top-field-first.
* WARNING : zvbi doesn't support bottom-field-first. */
self->zvbi_decoder.synchronous = TRUE;
/* Specify the services you want. Adjust based on whether we
* have PAL or NTSC */
vbi_raw_decoder_add_services (&self->zvbi_decoder,
VBI_SLICED_CAPTION_525, /* strict */ 0);
} else
self->compatible_format = FALSE;
return TRUE;
}
static GstFlowReturn
gst_line_21_decoder_prepare_output_buffer (GstBaseTransform * trans,
GstBuffer * in, GstBuffer ** out)
{
GstLine21Decoder *self = (GstLine21Decoder *) trans;
GST_DEBUG_OBJECT (trans, "compatible_format:%d", self->compatible_format);
if (self->compatible_format) {
/* Make the output buffer writable */
*out = gst_buffer_make_writable (in);
return GST_FLOW_OK;
}
return
GST_BASE_TRANSFORM_CLASS
(gst_line_21_decoder_parent_class)->prepare_output_buffer (trans, in,
out);
}
static void
convert_line_v210_luma (const guint8 * orig, guint8 * dest, guint width)
{
guint i;
guint32 a, b, c, d;
guint8 *y = dest;
for (i = 0; i < width - 5; i += 6) {
a = GST_READ_UINT32_LE (orig + (i / 6) * 16 + 0);
b = GST_READ_UINT32_LE (orig + (i / 6) * 16 + 4);
c = GST_READ_UINT32_LE (orig + (i / 6) * 16 + 8);
d = GST_READ_UINT32_LE (orig + (i / 6) * 16 + 12);
*y++ = (a >> 12) & 0xff;
*y++ = (b >> 2) & 0xff;
*y++ = (b >> 22) & 0xff;
*y++ = (c >> 12) & 0xff;
*y++ = (d >> 2) & 0xff;
*y++ = (d >> 22) & 0xff;
}
}
static guint8 *
get_video_data (GstLine21Decoder * self, GstVideoFrame * frame, gint line)
{
guint8 *data = self->converted_lines;
guint8 *v210;
if (!self->convert_v210)
return (guint8 *) GST_VIDEO_FRAME_PLANE_DATA (frame,
0) + line * GST_VIDEO_INFO_COMP_STRIDE (self->info, 0);
v210 = (guint8 *)
GST_VIDEO_FRAME_PLANE_DATA (frame,
0) + line * GST_VIDEO_FRAME_COMP_STRIDE (frame, 0);
/* Convert v210 to I420 */
convert_line_v210_luma (v210, data, GST_VIDEO_FRAME_WIDTH (frame));
v210 += GST_VIDEO_FRAME_COMP_STRIDE (frame, 0);
convert_line_v210_luma (v210, data + GST_VIDEO_INFO_COMP_STRIDE (self->info,
0), GST_VIDEO_FRAME_WIDTH (frame));
GST_MEMDUMP ("converted", self->converted_lines, 64);
return self->converted_lines;
}
/* Call this to scan for CC
* Returns TRUE if it was found and set, else FALSE */
static gboolean
gst_line_21_decoder_scan (GstLine21Decoder * self, GstVideoFrame * frame)
{
gint i;
vbi_sliced sliced[52];
gboolean found = FALSE;
guint8 *data;
GST_DEBUG_OBJECT (self, "Starting probing. max_line_probes:%d",
self->max_line_probes);
i = self->line21_offset;
if (i == -1) {
GST_DEBUG_OBJECT (self, "Scanning from the beginning");
i = 0;
}
for (; i < self->max_line_probes; i++) {
gint n_lines;
data = get_video_data (self, frame, i);
/* Scan until we get n_lines == 2 */
n_lines = vbi_raw_decode (&self->zvbi_decoder, data, sliced);
GST_DEBUG_OBJECT (self, "i:%d n_lines:%d", i, n_lines);
if (n_lines == 2) {
GST_DEBUG_OBJECT (self, "Found 2 CC lines at offset %d", i);
self->line21_offset = i;
found = TRUE;
break;
}
}
if (!found) {
GST_DEBUG_OBJECT (self, "No CC found");
self->line21_offset = -1;
} else {
guint8 ccdata[6] = { 0xfc, 0x80, 0x80, 0xfd, 0x80, 0x80 }; /* Initialize the ccdata */
ccdata[1] = sliced[0].data[0];
ccdata[2] = sliced[0].data[1];
ccdata[4] = sliced[1].data[0];
ccdata[5] = sliced[1].data[1];
gst_buffer_add_video_caption_meta (frame->buffer,
GST_VIDEO_CAPTION_TYPE_CEA608_IN_CEA708_RAW, ccdata, 6);
GST_TRACE_OBJECT (self,
"Got CC 0x%02x 0x%02x / 0x%02x 0x%02x '%c%c / %c%c'", ccdata[1],
ccdata[2], ccdata[4], ccdata[5],
g_ascii_isprint (ccdata[1] & 0x7f) ? ccdata[1] & 0x7f : '.',
g_ascii_isprint (ccdata[2] & 0x7f) ? ccdata[2] & 0x7f : '.',
g_ascii_isprint (ccdata[4] & 0x7f) ? ccdata[4] & 0x7f : '.',
g_ascii_isprint (ccdata[5] & 0x7f) ? ccdata[5] & 0x7f : '.');
}
return found;
}
static GstFlowReturn
gst_line_21_decoder_transform_ip (GstVideoFilter * filter,
GstVideoFrame * frame)
{
GstLine21Decoder *self = (GstLine21Decoder *) filter;
if (!self->compatible_format)
return GST_FLOW_OK;
gst_line_21_decoder_scan (self, frame);
return GST_FLOW_OK;
}
static GstStateChangeReturn
gst_line_21_decoder_change_state (GstElement * element,
GstStateChange transition)
{
GstStateChangeReturn ret;
GstLine21Decoder *filter = GST_LINE21DECODER (element);
switch (transition) {
case GST_STATE_CHANGE_NULL_TO_READY:
break;
case GST_STATE_CHANGE_READY_TO_PAUSED:
break;
case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
break;
default:
break;
}
ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
if (ret != GST_STATE_CHANGE_SUCCESS)
return ret;
switch (transition) {
case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
break;
case GST_STATE_CHANGE_PAUSED_TO_READY:
gst_line_21_decoder_reset (filter);
break;
case GST_STATE_CHANGE_READY_TO_NULL:
default:
break;
}
return ret;
}
static void
gst_line_21_decoder_finalize (GObject * object)
{
G_OBJECT_CLASS (parent_class)->finalize (object);
}

73
ext/closedcaption/gstline21dec.h Normal file
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@ -0,0 +1,73 @@
/*
* GStreamer
* Copyright (C) 2018 Edward Hervey <edward@centricular.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifndef __GST_LINE21DECODER_H__
#define __GST_LINE21DECODER_H__
#include <gst/gst.h>
#include <gst/video/video.h>
#include <gst/video/video-anc.h>
#include "decoder.h"
G_BEGIN_DECLS
#define GST_TYPE_LINE21DECODER \
(gst_line_21_decoder_get_type())
#define GST_LINE21DECODER(obj) \
(G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_LINE21DECODER,GstLine21Decoder))
#define GST_LINE21DECODER_CLASS(klass) \
(G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_LINE21DECODER,GstLine21DecoderClass))
#define GST_IS_LINE21DECODER(obj) \
(G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_LINE21DECODER))
#define GST_IS_LINE21DECODER_CLASS(klass) \
(G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_LINE21DECODER))
typedef struct _GstLine21Decoder GstLine21Decoder;
typedef struct _GstLine21DecoderClass GstLine21DecoderClass;
struct _GstLine21Decoder
{
GstVideoFilter parent;
gboolean compatible_format;
vbi_raw_decoder zvbi_decoder;
/* Offset (in lines) to "line 21" in the incoming stream */
gint line21_offset;
/* Maximum number of lines to probe when looking for CC */
gint max_line_probes;
/* Whether input data is v210 and needs to be converted before
* processing */
gboolean convert_v210;
guint8 *converted_lines;
GstVideoInfo *info;
};
struct _GstLine21DecoderClass
{
GstVideoFilterClass parent_class;
};
GType gst_line_21_decoder_get_type (void);
G_END_DECLS
#endif /* __GST_LINE21DECODER_H__ */