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https://gitlab.freedesktop.org/gstreamer/gstreamer.git
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8c60e42070
Helps with debugging issues. And also remove unused variable (opcr) This will also allow us in the future to properly detect: * random-access location (to enable keyframe observation and potentially seeking * discont location (to properly handle resets) * splice location (to properly handle new stream changes)
440 lines
12 KiB
C
440 lines
12 KiB
C
/*
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* pesparse.c : MPEG PES parsing utility
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* Copyright (C) 2011 Edward Hervey <bilboed@gmail.com>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <stdlib.h>
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#include <string.h>
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#include <glib.h>
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#include "pesparse.h"
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GST_DEBUG_CATEGORY_STATIC (pes_parser_debug);
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#define GST_CAT_DEFAULT pes_parser_debug
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/**
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* mpegts_parse_pes_header:
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* @data: data to parse (starting from, and including, the sync code)
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* @length: size of @data in bytes
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* @res: PESHeader to fill (only valid with #PES_PARSING_OK.
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* @offset: Offset in @data to the data to parse. If #PES_PARSING_OK, offset to
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* first byte of data after the header.
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*
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* Parses the mpeg-ts PES header located in @data into the @res.
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*
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* Returns: #PES_PARSING_OK if the header was fully parsed and valid,
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* #PES_PARSING_BAD if the header is invalid, or #PES_PARSING_NEED_MORE if more data
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* is needed to properly parse the header.
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*/
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PESParsingResult
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mpegts_parse_pes_header (const guint8 * data, gsize length, PESHeader * res,
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gint * offset)
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{
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PESParsingResult ret = PES_PARSING_NEED_MORE;
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gsize origlength = length;
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const guint8 *origdata = data;
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guint32 val32;
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guint8 val8, flags;
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g_return_val_if_fail (res != NULL, PES_PARSING_BAD);
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g_return_val_if_fail (offset != NULL, PES_PARSING_BAD);
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g_return_val_if_fail (*offset < length, PES_PARSING_BAD);
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data += *offset;
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length -= *offset;
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/* The smallest valid PES header is 6 bytes (prefix + stream_id + length) */
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if (G_UNLIKELY (length < 6))
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goto need_more_data;
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val32 = GST_READ_UINT32_BE (data);
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data += 4;
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length -= 4;
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if (G_UNLIKELY ((val32 & 0xffffff00) != 0x00000100))
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goto bad_start_code;
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/* Clear the header */
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memset (res, 0, sizeof (PESHeader));
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res->PTS = -1;
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res->DTS = -1;
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res->ESCR = -1;
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res->stream_id = val32 & 0x000000ff;
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res->packet_length = GST_READ_UINT16_BE (data);
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if (res->packet_length)
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res->packet_length += 6;
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data += 2;
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length -= 2;
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GST_LOG ("stream_id : 0x%08x , packet_length : %d", res->stream_id,
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res->packet_length);
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/* Jump if we don't need to parse anything more */
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if (G_UNLIKELY (res->stream_id == 0xbc || res->stream_id == 0xbe
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|| res->stream_id == 0xbf || (res->stream_id >= 0xf0
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&& res->stream_id <= 0xf2) || res->stream_id == 0xff
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|| res->stream_id == 0xf8))
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goto done_parsing;
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if (G_UNLIKELY (length < 3))
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goto need_more_data;
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/* '10' 2
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* PES_scrambling_control 2
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* PES_priority 1
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* data_alignment_indicator 1
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* copyright 1
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* original_or_copy 1 */
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val8 = *data++;
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if (G_UNLIKELY ((val8 & 0xc0) != 0x80))
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goto bad_marker_1;
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res->scrambling_control = (val8 >> 4) & 0x3;
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res->flags = val8 & 0xf;
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GST_LOG ("scrambling_control 0x%0x", res->scrambling_control);
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GST_LOG ("flags_1: %s%s%s%s%s",
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val8 & 0x08 ? "priority " : "",
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val8 & 0x04 ? "data_alignment " : "",
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val8 & 0x02 ? "copyright " : "",
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val8 & 0x01 ? "original_or_copy " : "", val8 & 0x0f ? "" : "<none>");
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/* PTS_DTS_flags 2
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* ESCR_flag 1
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* ES_rate_flag 1
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* DSM_trick_mode_flag 1
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* additional_copy_info_flag 1
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* PES_CRC_flag 1
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* PES_extension_flag 1*/
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flags = *data++;
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GST_LOG ("flags_2: %s%s%s%s%s%s%s%s%s",
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flags & 0x80 ? "PTS " : "",
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flags & 0x40 ? "DTS " : "",
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flags & 0x20 ? "ESCR" : "",
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flags & 0x10 ? "ES_rate " : "",
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flags & 0x08 ? "DSM_trick_mode " : "",
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flags & 0x04 ? "additional_copy_info " : "",
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flags & 0x02 ? "CRC " : "",
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flags & 0x01 ? "extension " : "", flags ? "" : "<none>");
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/* PES_header_data_length 8 */
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res->header_size = *data++;
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length -= 3;
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if (G_UNLIKELY (length < res->header_size))
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goto need_more_data;
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res->header_size += 9; /* We add 9 since that's the offset
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* of the field in the header*/
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GST_DEBUG ("header_size : %d", res->header_size);
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/* PTS/DTS */
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/* PTS_DTS_flags == 0x01 is invalid */
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if (G_UNLIKELY ((flags >> 6) == 0x01)) {
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GST_WARNING ("Invalid PTS_DTS_flag (0x01 is forbidden)");
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}
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if ((flags & 0x80) == 0x80) {
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/* PTS */
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if (G_UNLIKELY (length < 5))
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goto need_more_data;
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READ_TS (data, res->PTS, bad_PTS_value);
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length -= 5;
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GST_LOG ("PTS %" G_GUINT64_FORMAT " %" GST_TIME_FORMAT,
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res->PTS, GST_TIME_ARGS (MPEGTIME_TO_GSTTIME (res->PTS)));
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}
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if ((flags & 0x40) == 0x40) {
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/* DTS */
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if (G_UNLIKELY (length < 5))
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goto need_more_data;
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READ_TS (data, res->DTS, bad_DTS_value);
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length -= 5;
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GST_LOG ("DTS %" G_GUINT64_FORMAT " %" GST_TIME_FORMAT,
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res->DTS, GST_TIME_ARGS (MPEGTIME_TO_GSTTIME (res->DTS)));
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}
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if (flags & 0x20) {
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/* ESCR */
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if (G_UNLIKELY (length < 5))
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goto need_more_data;
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READ_TS (data, res->ESCR, bad_ESCR_value);
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length -= 5;
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GST_LOG ("ESCR %" G_GUINT64_FORMAT " %" GST_TIME_FORMAT,
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res->ESCR, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (res->ESCR)));
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}
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if (flags & 0x10) {
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/* ES_rate */
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if (G_UNLIKELY (length < 3))
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goto need_more_data;
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val32 = GST_READ_UINT32_BE (data);
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data += 3;
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length -= 3;
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if (G_UNLIKELY ((val32 & 0x80000100) != 0x80000100))
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goto bad_ES_rate;
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res->ES_rate = ((val32 >> 9) & 0x003fffff) * 50;
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GST_LOG ("ES_rate : %d", res->ES_rate);
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}
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if (flags & 0x08) {
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/* DSM trick mode */
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if (G_UNLIKELY (length < 1))
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goto need_more_data;
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val8 = *data++;
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length -= 1;
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res->trick_mode = val8 >> 5;
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GST_LOG ("trick_mode 0x%x", res->trick_mode);
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switch (res->trick_mode) {
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case PES_TRICK_MODE_FAST_FORWARD:
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case PES_TRICK_MODE_FAST_REVERSE:
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res->intra_slice_refresh = (val8 >> 2) & 0x1;
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res->frequency_truncation = val8 & 0x3;
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/* passthrough */
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case PES_TRICK_MODE_FREEZE_FRAME:
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res->field_id = (val8 >> 3) & 0x3;
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break;
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case PES_TRICK_MODE_SLOW_MOTION:
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case PES_TRICK_MODE_SLOW_REVERSE:
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res->rep_cntrl = val8 & 0x1f;
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break;
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default:
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break;
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}
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}
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if (flags & 0x04) {
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/* additional copy info */
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if (G_UNLIKELY (length < 1))
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goto need_more_data;
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val8 = *data++;
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length -= 1;
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if (G_UNLIKELY (!(val8 & 0x80)))
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goto bad_original_copy_info_marker;
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res->additional_copy_info = val8 & 0x7f;
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GST_LOG ("additional_copy_info : 0x%x", res->additional_copy_info);
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}
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if (flags & 0x02) {
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/* CRC */
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if (G_UNLIKELY (length < 2))
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goto need_more_data;
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res->previous_PES_packet_CRC = GST_READ_UINT16_BE (data);
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GST_LOG ("previous_PES_packet_CRC : 0x%x", res->previous_PES_packet_CRC);
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data += 2;
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length -= 2;
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}
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/* jump if we don't have a PES extension */
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if (!(flags & 0x01))
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goto stuffing_byte;
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if (G_UNLIKELY (length < 1))
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goto need_more_data;
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/* PES extension */
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flags = *data++;
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length -= 1;
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GST_DEBUG ("PES_extension_flag 0x%02x", flags);
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if (flags & 0x80) {
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/* PES_private data */
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if (G_UNLIKELY (length < 16))
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goto need_more_data;
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res->private_data = data;
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GST_MEMDUMP ("private_data", data, 16);
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data += 16;
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length -= 16;
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}
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if (flags & 0x40) {
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/* pack_header_field */
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if (G_UNLIKELY (length < 1))
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goto need_more_data;
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val8 = *data++;
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length -= 1;
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if (G_UNLIKELY (length < val8))
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goto need_more_data;
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res->pack_header_size = val8;
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res->pack_header = data;
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GST_MEMDUMP ("Pack header data", res->pack_header, res->pack_header_size);
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data += val8;
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length -= val8;
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}
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if (flags & 0x20) {
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/* sequence counter */
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if (G_UNLIKELY (length < 2))
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goto need_more_data;
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val8 = *data++;
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/* GRMBL, this is most often wrong */
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if (G_UNLIKELY ((val8 & 0x80) != 0x80))
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goto bad_sequence_marker1;
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res->program_packet_sequence_counter = val8 & 0x7f;
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GST_LOG ("program_packet_sequence_counter %d",
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res->program_packet_sequence_counter);
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val8 = *data++;
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/* GRMBL, this is most often wrong */
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if (G_UNLIKELY ((val8 & 0x80) != 0x80))
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goto bad_sequence_marker2;
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res->MPEG1_MPEG2_identifier = (val8 >> 6) & 0x1;
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res->original_stuff_length = val8 & 0x3f;
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GST_LOG ("MPEG1_MPEG2_identifier : %d , original_stuff_length : %d",
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res->MPEG1_MPEG2_identifier, res->original_stuff_length);
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length -= 2;
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}
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if (flags & 0x10) {
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/* P-STD */
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if (G_UNLIKELY (length < 2))
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goto need_more_data;
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val8 = *data;
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if (G_UNLIKELY ((val8 & 0xc0) != 0x40))
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goto bad_P_STD_marker;
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res->P_STD_buffer_size =
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(GST_READ_UINT16_BE (data) & 0x1fff) << (val8 & 0x20) ? 10 : 7;
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GST_LOG ("P_STD_buffer_size : %d", res->P_STD_buffer_size);
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data += 2;
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length -= 2;
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}
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if (flags & 0x01) {
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/* Extension flag 2 */
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if (G_UNLIKELY (length < 1))
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goto need_more_data;
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val8 = *data++;
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length -= 1;
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if (!(val8 & 0x80))
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goto bad_extension_marker_2;
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res->extension_field_length = val8 & 0x7f;
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if (G_UNLIKELY (length < res->extension_field_length + 1))
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goto need_more_data;
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GST_LOG ("extension_field_length : %" G_GSIZE_FORMAT,
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res->extension_field_length);
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if (res->extension_field_length) {
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flags = *data++;
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/* Only valid if stream_id_extension_flag == 0x0 */
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if (!(flags & 0x80)) {
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res->stream_id_extension = flags & 0x7f;
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GST_LOG ("stream_id_extension : 0x%02x", res->stream_id_extension);
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res->stream_id_extension_data = data;
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GST_MEMDUMP ("stream_id_extension_data",
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res->stream_id_extension_data, res->extension_field_length);
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} else {
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GST_LOG ("tref_extension : %d", flags & 0x01);
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}
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data += res->extension_field_length;
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}
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length -= res->extension_field_length + 1;
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}
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stuffing_byte:
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/* Go to the expected data start position */
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data = origdata + res->header_size;
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length = origlength - res->header_size;
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done_parsing:
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GST_DEBUG ("origlength:%" G_GSIZE_FORMAT ", length:%" G_GSIZE_FORMAT,
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origlength, length);
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res->header_size = origlength - length;
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*offset += res->header_size;
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ret = PES_PARSING_OK;
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return ret;
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/* Errors */
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need_more_data:
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GST_DEBUG ("Not enough data to parse PES header");
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return ret;
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bad_start_code:
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GST_WARNING ("Wrong packet start code 0x%x != 0x000001xx", val32);
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return PES_PARSING_BAD;
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bad_marker_1:
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GST_WARNING ("Wrong '0x10' marker before PES_scrambling_control (0x%02x)",
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val8);
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return PES_PARSING_BAD;
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bad_PTS_value:
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GST_WARNING ("bad PTS value");
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return PES_PARSING_BAD;
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bad_DTS_value:
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GST_WARNING ("bad DTS value");
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return PES_PARSING_BAD;
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bad_ESCR_value:
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GST_WARNING ("bad ESCR value");
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return PES_PARSING_BAD;
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bad_ES_rate:
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GST_WARNING ("Invalid ES_rate markers 0x%0x", val32);
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return PES_PARSING_BAD;
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bad_original_copy_info_marker:
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GST_WARNING ("Invalid original_copy_info marker bit: 0x%0x", val8);
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return PES_PARSING_BAD;
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bad_sequence_marker1:
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GST_WARNING ("Invalid program_packet_sequence_counter marker 0x%0x", val8);
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return PES_PARSING_BAD;
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bad_sequence_marker2:
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GST_WARNING ("Invalid program_packet_sequence_counter marker 0x%0x", val8);
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return PES_PARSING_BAD;
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bad_P_STD_marker:
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GST_WARNING ("Invalid P-STD_buffer marker 0x%0x", val8);
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return PES_PARSING_BAD;
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bad_extension_marker_2:
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GST_WARNING ("Invalid extension_field_2 marker 0x%0x", val8);
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return PES_PARSING_BAD;
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}
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void
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init_pes_parser (void)
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{
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GST_DEBUG_CATEGORY_INIT (pes_parser_debug, "pesparser", 0, "MPEG PES parser");
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}
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