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gstreamer/gst/videoparsers/gstvideoparseutils.c
Vivia Nikolaidou 31d5d04bb1 videoparseutils: Only add a single closed caption meta 
Otherwise, having a stream go through a parser multiple times would
result in duplicate closed caption meta.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1396>
2020-07-03 08:25:54 +00:00

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/* GStreamer
* Copyright (2019) Collabora Ltd.
* Contact: Aaron Boxer <aaron.boxer@collabora.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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include <gst/base/base.h>
#include <gst/pbutils/pbutils.h>
#include <gst/video/video.h>
#include <gst/base/gstbitreader.h>
#include <gstvideoparseutils.h>
GST_DEBUG_CATEGORY_EXTERN (videoparseutils_debug);
#define GST_CAT_DEFAULT videoparseutils_debug
static gboolean gst_video_parse_utils_parse_bar (const guint8 * data,
gsize size, guint field, GstVideoBarData * bar);
static gboolean gst_video_parse_utils_parse_afd (const guint8 data,
GstVideoAFD * afd, GstVideoAFDSpec spec);
/*
* gst_video_parse_user_data:
* @elt: #GstElement that is parsing user data
* @user_data: #GstVideoParseUserData struct to hold parsed closed caption, bar and AFD data
* @br: #GstByteReader attached to buffer of user data
* @field: 0 for progressive or field 1 and 1 for field 2
* @provider_code: Currently, only (US) ATSC and DirecTV provider codes are supported
*
* Parse user data and store in @user_data
*/
void
gst_video_parse_user_data (GstElement * elt, GstVideoParseUserData * user_data,
GstByteReader * br, guint8 field, guint16 provider_code)
{
guint32 user_data_id = 0;
guint8 user_data_type_code = 0;
gboolean a53_process_708_cc_data = FALSE;
gboolean process_708_em_data = FALSE;
guint8 temp = 0;
guint8 cc_count;
guint cc_size;
guint bar_size = 0;
const guint8 *data = NULL;
guint8 directv_size = 0;
/* https://en.wikipedia.org/wiki/CEA-708#Picture_User_Data */
switch (provider_code) {
case ITU_T_T35_MANUFACTURER_US_ATSC:
if (!gst_byte_reader_peek_uint32_be (br, &user_data_id)) {
GST_WARNING_OBJECT (elt, "Missing user data id, ignoring");
return;
}
switch (user_data_id) {
case A53_USER_DATA_ID_DTG1:
case A53_USER_DATA_ID_GA94:
/* ANSI/SCTE 128-2010a section 8.1.2 */
if (!gst_byte_reader_get_uint32_be (br, &user_data_id)) {
GST_WARNING_OBJECT (elt, "Missing user data id, ignoring");
return;
}
break;
default:
/* check for SCTE 20 */
if (user_data_id >> 24 == A53_USER_DATA_TYPE_CODE_CC_DATA) {
user_data_id = USER_DATA_ID_SCTE_20_CC;
gst_byte_reader_skip (br, 1);
}
break;
}
break;
case ITU_T_T35_MANUFACTURER_US_DIRECTV:
user_data_id = USER_DATA_ID_DIRECTV_CC;
break;
default:
GST_LOG_OBJECT (elt, "Unsupported provider code %d", provider_code);
return;
}
switch (user_data_id) {
case USER_DATA_ID_SCTE_20_CC:
GST_DEBUG_OBJECT (elt, "Unsupported SCTE 20 closed captions");
break;
case A53_USER_DATA_ID_DTG1:
if (!gst_byte_reader_get_uint8 (br, &temp)) {
GST_WARNING_OBJECT (elt, "Missing active format flag, ignoring");
break;
}
/* check active format flag for presence of AFD */
if (temp & 0x40) {
if (!gst_byte_reader_get_uint8 (br, &temp)) {
GST_WARNING_OBJECT (elt,
"Missing active format description, ignoring");
break;
}
GST_LOG_OBJECT (elt, "parsed active format description (AFD): %d",
temp);
user_data->afd_spec = GST_VIDEO_AFD_SPEC_ATSC_A53;
user_data->afd = temp;
user_data->active_format_flag = TRUE;
} else {
user_data->active_format_flag = FALSE;
}
user_data->has_afd = TRUE;
user_data->field = field;
break;
case USER_DATA_ID_DIRECTV_CC:
case A53_USER_DATA_ID_GA94:
if (!gst_byte_reader_get_uint8 (br, &user_data_type_code)) {
GST_WARNING_OBJECT (elt, "Missing user data type code, ignoring");
break;
}
if (provider_code == ITU_T_T35_MANUFACTURER_US_DIRECTV) {
if (!gst_byte_reader_get_uint8 (br, &directv_size)) {
GST_WARNING_OBJECT (elt, "Missing DirecTV size, ignoring");
break;
}
}
switch (user_data_type_code) {
case A53_USER_DATA_TYPE_CODE_CC_DATA:
if (gst_byte_reader_get_remaining (br) < 7) {
GST_WARNING_OBJECT (elt,
"Closed caption data packet too short, ignoring");
break;
}
if (!gst_byte_reader_get_uint8 (br, &cc_count)) {
GST_WARNING_OBJECT (elt, "Missing closed caption count, ignoring");
break;
}
/* A53 part 4 closed captions */
a53_process_708_cc_data =
(cc_count & CEA_708_PROCESS_CC_DATA_FLAG) != 0;
if (!a53_process_708_cc_data) {
GST_WARNING_OBJECT (elt,
"ignoring closed captions as CEA_708_PROCESS_CC_DATA_FLAG is not set");
}
process_708_em_data = (cc_count & CEA_708_PROCESS_EM_DATA_FLAG) != 0;
if (!process_708_em_data) {
GST_WARNING_OBJECT (elt,
"CEA_708_PROCESS_EM_DATA_FLAG flag is not set");
}
if (!gst_byte_reader_get_uint8 (br, &temp)) {
GST_WARNING_OBJECT (elt, "Missing em bits, ignoring");
break;
}
if (temp != 0xff) {
GST_WARNING_OBJECT (elt, "em data does not equal 0xFF");
}
process_708_em_data = process_708_em_data && (temp == 0xff);
/* ignore process_708_em_data as there is content that doesn't follow spec for this field */
if (a53_process_708_cc_data) {
cc_count = cc_count & 0x1f;
cc_size = cc_count * 3;
if (cc_size == 0 || cc_size > gst_byte_reader_get_remaining (br)) {
GST_DEBUG_OBJECT (elt,
"ignoring closed captions, not enough data");
break;
}
/* Shouldn't really happen so let's not go out of our way to handle it */
if (user_data->closedcaptions_size > 0)
GST_WARNING_OBJECT (elt, "unused pending closed captions!");
g_assert (cc_size <= sizeof (user_data->closedcaptions));
if (!gst_byte_reader_get_data (br, cc_size, &data))
break;
memcpy (user_data->closedcaptions, data, cc_size);
user_data->closedcaptions_size = cc_size;
user_data->closedcaptions_type = GST_VIDEO_CAPTION_TYPE_CEA708_RAW;
user_data->field = field;
GST_DEBUG_OBJECT (elt, "CEA-708 closed captions, %u bytes",
cc_size);
}
break;
case A53_USER_DATA_TYPE_CODE_SCTE_21_EIA_608_CC_DATA:
GST_DEBUG_OBJECT (elt, "Unsupported SCTE 21 closed captions");
break;
case A53_USER_DATA_TYPE_CODE_BAR_DATA:
bar_size = gst_byte_reader_get_remaining (br);
if (bar_size == 0) {
GST_WARNING_OBJECT (elt, "Bar data packet too short, ignoring");
break;
}
if (bar_size > GST_VIDEO_BAR_MAX_BYTES) {
GST_WARNING_OBJECT (elt,
"Bar data packet of size %d is too long, ignoring", bar_size);
break;
}
if (!gst_byte_reader_get_data (br, bar_size, &data))
break;
memcpy (user_data->bar_data, data, bar_size);
user_data->bar_data_size = bar_size;
user_data->has_bar_data = TRUE;
user_data->field = field;
GST_DEBUG_OBJECT (elt, "Bar data, %u bytes", bar_size);
break;
default:
GST_DEBUG_OBJECT (elt,
"Unrecognized user data type code %d of size %d",
user_data_type_code, gst_byte_reader_get_remaining (br));
break;
}
break;
default:
GST_DEBUG_OBJECT (elt,
"Unrecognized user data id %d of size %d", user_data_id,
gst_byte_reader_get_remaining (br));
break;
}
}
/*
* gst_video_push_user_data:
* @elt: #GstElement that is pushing user data
* @user_data: #GstVideoParseUserData holding parsed closed caption, bar and AFD data
* @buf: #GstBuffer that receives the parsed data
*
* After user data has been parsed, add the data to @buf
*/
void
gst_video_push_user_data (GstElement * elt, GstVideoParseUserData * user_data,
GstBuffer * buf)
{
/* 1. handle closed captions */
if (user_data->closedcaptions_size > 0) {
if (!gst_buffer_get_meta (buf, GST_VIDEO_CAPTION_META_API_TYPE)) {
gst_buffer_add_video_caption_meta (buf,
user_data->closedcaptions_type, user_data->closedcaptions,
user_data->closedcaptions_size);
} else {
GST_DEBUG_OBJECT (elt, "Closed caption data already found on buffer, "
"discarding to avoid duplication");
}
user_data->closedcaptions_type = GST_VIDEO_CAPTION_TYPE_UNKNOWN;
user_data->closedcaptions_size = 0;
}
/* 2. handle AFD */
if (user_data->has_afd) {
GstVideoAFD afd;
afd.field = 0;
afd.aspect_ratio = GST_VIDEO_AFD_ASPECT_RATIO_UNDEFINED;
afd.spec = GST_VIDEO_AFD_SPEC_ATSC_A53;
afd.afd = GST_VIDEO_AFD_UNAVAILABLE;
if (gst_video_parse_utils_parse_afd (user_data->afd, &afd, afd.spec)) {
gst_buffer_add_video_afd_meta (buf, afd.field, afd.spec, afd.afd);
} else {
GST_WARNING_OBJECT (elt, "Invalid AFD value %d", user_data->afd);
}
} else if (user_data->active_format_flag) {
/* AFD was present, but now it is no longer present */
GST_DEBUG_OBJECT (elt,
"AFD was present in previous frame, now no longer present");
user_data->active_format_flag = 0;
}
user_data->has_afd = FALSE;
/* 3. handle Bar data */
if (user_data->has_bar_data) {
GstVideoBarData data;
if (gst_video_parse_utils_parse_bar (user_data->bar_data,
user_data->bar_data_size, user_data->field, &data)) {
gst_buffer_add_video_bar_meta (buf, data.field, data.is_letterbox,
data.bar_data[0], data.bar_data[1]);
} else {
GST_WARNING_OBJECT (elt, "Invalid Bar data");
}
} else if (user_data->bar_data_size) {
/* bar data was present, but now it is no longer present */
GST_DEBUG_OBJECT (elt,
"Bar data was present in previous frame, now no longer present");
user_data->bar_data_size = 0;
}
user_data->has_bar_data = FALSE;
}
/*
* gst_video_parse_utils_parse_bar:
* @data: bar data array
* @size:size of bar data array
* @bar: #GstVideoBarData structure
*
* Parse bar data bytes into #GstVideoBarData structure
*
* See Table in https://www.atsc.org/wp-content/uploads/2015/03/a_53-Part-4-2009.pdf
*
* Returns: TRUE if parsing was successful, otherwise FALSE
*/
static gboolean
gst_video_parse_utils_parse_bar (const guint8 * data, gsize size,
guint field, GstVideoBarData * bar)
{
guint8 temp;
int i = 0;
guint8 bar_flags[4];
guint16 bar_vals[4] = { 0, 0, 0, 0 };
GstBitReader bar_tender;
/* there must be at least one byte, and not more than GST_VIDEO_BAR_MAX_BYTES bytes */
if (!bar || size == 0 || size > GST_VIDEO_BAR_MAX_BYTES)
return FALSE;
gst_bit_reader_init (&bar_tender, data, size);
/* parse bar flags */
for (i = 0; i < 4; ++i) {
if (!gst_bit_reader_get_bits_uint8 (&bar_tender, bar_flags + i, 1))
return FALSE;
}
/* the next four bits must equal 1111 */
if (!gst_bit_reader_get_bits_uint8 (&bar_tender, &temp, 4) || temp != 0xF)
return FALSE;
/* parse bar values */
for (i = 0; i < 4; ++i) {
if (bar_flags[i]) {
/* the next two bits must equal 11 */
if (!gst_bit_reader_get_bits_uint8 (&bar_tender, &temp, 2) || temp != 0x3)
return FALSE;
if (!gst_bit_reader_get_bits_uint16 (&bar_tender, bar_vals + i, 14))
return FALSE;
}
}
/* bars are signaled in pairs: either top/bottom or left/right, but not both */
if ((bar_flags[0] != bar_flags[1]) || (bar_flags[2] != bar_flags[3]))
return FALSE;
if (bar_flags[0] && bar_flags[2])
return FALSE;
bar->is_letterbox = bar_flags[0];
if (bar->is_letterbox) {
bar->bar_data[0] = bar_vals[0];
bar->bar_data[1] = bar_vals[1];
} else {
bar->bar_data[0] = bar_vals[2];
bar->bar_data[1] = bar_vals[3];
}
bar->field = field;
return TRUE;
}
/*
* gst_video_parse_utils_parse_afd:
* @data: bar byte
* @afd: pointer to #GstVideoAFD struct
* @spec : #GstVideoAFDSpec indicating specification that applies to AFD byte
*
* Parse afd byte into #GstVideoAFD struct
*
* See:
*
* https://www.atsc.org/wp-content/uploads/2015/03/a_53-Part-4-2009.pdf
*
* https://en.wikipedia.org/wiki/Active_Format_Description#Complete_list_of_AFD_codes
*
* and
*
* SMPTE ST2016-1
*
* Returns: TRUE if parsing was successful, otherwise FALSE
*/
static gboolean
gst_video_parse_utils_parse_afd (const guint8 data, GstVideoAFD * afd,
GstVideoAFDSpec spec)
{
guint8 afd_data;
g_return_val_if_fail (afd != NULL, FALSE);
g_return_val_if_fail ((guint8) spec <= 2, FALSE);
switch (spec) {
case GST_VIDEO_AFD_SPEC_DVB_ETSI:
case GST_VIDEO_AFD_SPEC_ATSC_A53:
if ((data & 0x40) == 0)
return FALSE;
afd_data = data & 0xF;
break;
case GST_VIDEO_AFD_SPEC_SMPTE_ST2016_1:
if ((data & 0x80) || (data & 0x3))
return FALSE;
afd_data = data >> 3;
afd->aspect_ratio = (GstVideoAFDAspectRatio) (((data >> 2) & 1) + 1);
break;
default:
return FALSE;
}
/* AFD is stored in a nybble */
g_return_val_if_fail (afd_data <= 0xF, FALSE);
/* reserved values for all specifications */
g_return_val_if_fail (afd_data != 1 && (afd_data < 5 || afd_data > 7)
&& afd_data != 12, FALSE);
/* reserved for DVB/ETSI */
g_return_val_if_fail ((spec != GST_VIDEO_AFD_SPEC_DVB_ETSI)
|| (afd_data != 0), FALSE);
afd->spec = spec;
afd->afd = (GstVideoAFDValue) afd_data;
return TRUE;
}
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