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gstreamer/gst/mpegtsdemux/pesparse.c
Tim-Philipp Müller f0358aac16 tsdemux: remove unnecessary check 
This is not public API, use g_assert() instead of
g_return_if_fail(), so that it's compiled out in
releases. It's only called from our code, with &foo.
2015-07-08 14:50:00 +01:00

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/*
* pesparse.c : MPEG PES parsing utility
* Copyright (C) 2011 Edward Hervey <bilboed@gmail.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 <stdlib.h>
#include <string.h>
#include <glib.h>
#include "pesparse.h"
GST_DEBUG_CATEGORY_STATIC (pes_parser_debug);
#define GST_CAT_DEFAULT pes_parser_debug
/**
* mpegts_parse_pes_header:
* @data: data to parse (starting from, and including, the sync code)
* @length: size of @data in bytes
* @res: PESHeader to fill (only valid with #PES_PARSING_OK.
*
* Parses the mpeg-ts PES header located in @data into the @res.
*
* Returns: #PES_PARSING_OK if the header was fully parsed and valid,
* #PES_PARSING_BAD if the header is invalid, or #PES_PARSING_NEED_MORE if more data
* is needed to properly parse the header.
*/
PESParsingResult
mpegts_parse_pes_header (const guint8 * data, gsize length, PESHeader * res)
{
PESParsingResult ret = PES_PARSING_NEED_MORE;
gsize origlength = length;
const guint8 *origdata = data;
guint32 val32;
guint8 val8, flags;
g_assert (res != NULL);
/* The smallest valid PES header is 6 bytes (prefix + stream_id + length) */
if (G_UNLIKELY (length < 6))
goto need_more_data;
val32 = GST_READ_UINT32_BE (data);
data += 4;
length -= 4;
if (G_UNLIKELY ((val32 & 0xffffff00) != 0x00000100))
goto bad_start_code;
/* Clear the header */
memset (res, 0, sizeof (PESHeader));
res->PTS = -1;
res->DTS = -1;
res->ESCR = -1;
res->stream_id = val32 & 0x000000ff;
res->packet_length = GST_READ_UINT16_BE (data);
if (res->packet_length)
res->packet_length += 6;
data += 2;
length -= 2;
GST_LOG ("stream_id : 0x%08x , packet_length : %d", res->stream_id,
res->packet_length);
/* Jump if we don't need to parse anything more */
if (G_UNLIKELY (res->stream_id == 0xbc || res->stream_id == 0xbe
|| res->stream_id == 0xbf || (res->stream_id >= 0xf0
&& res->stream_id <= 0xf2) || res->stream_id == 0xff
|| res->stream_id == 0xf8))
goto done_parsing;
if (G_UNLIKELY (length < 3))
goto need_more_data;
/* '10' 2
* PES_scrambling_control 2
* PES_priority 1
* data_alignment_indicator 1
* copyright 1
* original_or_copy 1 */
val8 = *data++;
if (G_UNLIKELY ((val8 & 0xc0) != 0x80))
goto bad_marker_1;
res->scrambling_control = (val8 >> 4) & 0x3;
res->flags = val8 & 0xf;
GST_LOG ("scrambling_control 0x%0x", res->scrambling_control);
GST_LOG ("flags_1: %s%s%s%s%s",
val8 & 0x08 ? "priority " : "",
val8 & 0x04 ? "data_alignment " : "",
val8 & 0x02 ? "copyright " : "",
val8 & 0x01 ? "original_or_copy " : "", val8 & 0x0f ? "" : "<none>");
/* PTS_DTS_flags 2
* ESCR_flag 1
* ES_rate_flag 1
* DSM_trick_mode_flag 1
* additional_copy_info_flag 1
* PES_CRC_flag 1
* PES_extension_flag 1*/
flags = *data++;
GST_LOG ("flags_2: %s%s%s%s%s%s%s%s%s",
flags & 0x80 ? "PTS " : "",
flags & 0x40 ? "DTS " : "",
flags & 0x20 ? "ESCR" : "",
flags & 0x10 ? "ES_rate " : "",
flags & 0x08 ? "DSM_trick_mode " : "",
flags & 0x04 ? "additional_copy_info " : "",
flags & 0x02 ? "CRC " : "",
flags & 0x01 ? "extension " : "", flags ? "" : "<none>");
/* PES_header_data_length 8 */
res->header_size = *data++;
length -= 3;
if (G_UNLIKELY (length < res->header_size))
goto need_more_data;
res->header_size += 9; /* We add 9 since that's the offset
* of the field in the header*/
GST_DEBUG ("header_size : %d", res->header_size);
/* PTS/DTS */
/* PTS_DTS_flags == 0x01 is invalid */
if (G_UNLIKELY ((flags >> 6) == 0x01)) {
GST_WARNING ("Invalid PTS_DTS_flag (0x01 is forbidden)");
}
if ((flags & 0x80) == 0x80) {
/* PTS */
if (G_UNLIKELY (length < 5))
goto need_more_data;
READ_TS (data, res->PTS, bad_PTS_value);
length -= 5;
GST_LOG ("PTS %" G_GUINT64_FORMAT " %" GST_TIME_FORMAT,
res->PTS, GST_TIME_ARGS (MPEGTIME_TO_GSTTIME (res->PTS)));
}
if ((flags & 0x40) == 0x40) {
/* DTS */
if (G_UNLIKELY (length < 5))
goto need_more_data;
READ_TS (data, res->DTS, bad_DTS_value);
length -= 5;
GST_LOG ("DTS %" G_GUINT64_FORMAT " %" GST_TIME_FORMAT,
res->DTS, GST_TIME_ARGS (MPEGTIME_TO_GSTTIME (res->DTS)));
}
if (flags & 0x20) {
/* ESCR */
if (G_UNLIKELY (length < 5))
goto need_more_data;
READ_TS (data, res->ESCR, bad_ESCR_value);
length -= 5;
GST_LOG ("ESCR %" G_GUINT64_FORMAT " %" GST_TIME_FORMAT,
res->ESCR, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (res->ESCR)));
}
if (flags & 0x10) {
/* ES_rate */
if (G_UNLIKELY (length < 3))
goto need_more_data;
val32 = GST_READ_UINT32_BE (data);
data += 3;
length -= 3;
if (G_UNLIKELY ((val32 & 0x80000100) != 0x80000100))
goto bad_ES_rate;
res->ES_rate = ((val32 >> 9) & 0x003fffff) * 50;
GST_LOG ("ES_rate : %d", res->ES_rate);
}
if (flags & 0x08) {
/* DSM trick mode */
if (G_UNLIKELY (length < 1))
goto need_more_data;
val8 = *data++;
length -= 1;
res->trick_mode = val8 >> 5;
GST_LOG ("trick_mode 0x%x", res->trick_mode);
switch (res->trick_mode) {
case PES_TRICK_MODE_FAST_FORWARD:
case PES_TRICK_MODE_FAST_REVERSE:
res->intra_slice_refresh = (val8 >> 2) & 0x1;
res->frequency_truncation = val8 & 0x3;
/* passthrough */
case PES_TRICK_MODE_FREEZE_FRAME:
res->field_id = (val8 >> 3) & 0x3;
break;
case PES_TRICK_MODE_SLOW_MOTION:
case PES_TRICK_MODE_SLOW_REVERSE:
res->rep_cntrl = val8 & 0x1f;
break;
default:
break;
}
}
if (flags & 0x04) {
/* additional copy info */
if (G_UNLIKELY (length < 1))
goto need_more_data;
val8 = *data++;
length -= 1;
if (G_UNLIKELY (!(val8 & 0x80)))
goto bad_original_copy_info_marker;
res->additional_copy_info = val8 & 0x7f;
GST_LOG ("additional_copy_info : 0x%x", res->additional_copy_info);
}
if (flags & 0x02) {
/* CRC */
if (G_UNLIKELY (length < 2))
goto need_more_data;
res->previous_PES_packet_CRC = GST_READ_UINT16_BE (data);
GST_LOG ("previous_PES_packet_CRC : 0x%x", res->previous_PES_packet_CRC);
data += 2;
length -= 2;
}
/* jump if we don't have a PES extension */
if (!(flags & 0x01))
goto stuffing_byte;
if (G_UNLIKELY (length < 1))
goto need_more_data;
/* PES extension */
flags = *data++;
length -= 1;
GST_DEBUG ("PES_extension_flag: %s%s%s%s%s%s",
flags & 0x80 ? "PES_private_data " : "",
flags & 0x40 ? "pack_header_field " : "",
flags & 0x20 ? "program_packet_sequence_counter " : "",
flags & 0x10 ? "P-STD_buffer " : "",
flags & 0x01 ? "PES_extension_flag_2" : "", flags & 0xf1 ? "" : "<none>");
if (flags & 0x80) {
/* PES_private data */
if (G_UNLIKELY (length < 16))
goto need_more_data;
res->private_data = data;
GST_MEMDUMP ("private_data", data, 16);
data += 16;
length -= 16;
}
if (flags & 0x40) {
/* pack_header_field */
if (G_UNLIKELY (length < 1))
goto need_more_data;
val8 = *data++;
length -= 1;
if (G_UNLIKELY (length < val8))
goto need_more_data;
res->pack_header_size = val8;
res->pack_header = data;
GST_MEMDUMP ("Pack header data", res->pack_header, res->pack_header_size);
data += val8;
length -= val8;
}
if (flags & 0x20) {
/* sequence counter */
if (G_UNLIKELY (length < 2))
goto need_more_data;
val8 = *data++;
if (G_UNLIKELY ((val8 & 0x80) != 0x80))
goto bad_sequence_marker1;
res->program_packet_sequence_counter = val8 & 0x7f;
GST_LOG ("program_packet_sequence_counter %d",
res->program_packet_sequence_counter);
val8 = *data++;
if (G_UNLIKELY ((val8 & 0x80) != 0x80))
goto bad_sequence_marker2;
res->MPEG1_MPEG2_identifier = (val8 >> 6) & 0x1;
res->original_stuff_length = val8 & 0x3f;
GST_LOG ("MPEG1_MPEG2_identifier : %d , original_stuff_length : %d",
res->MPEG1_MPEG2_identifier, res->original_stuff_length);
length -= 2;
}
if (flags & 0x10) {
/* P-STD */
if (G_UNLIKELY (length < 2))
goto need_more_data;
val8 = *data;
if (G_UNLIKELY ((val8 & 0xc0) != 0x40))
goto bad_P_STD_marker;
res->P_STD_buffer_size =
(GST_READ_UINT16_BE (data) & 0x1fff) << (val8 & 0x20) ? 10 : 7;
GST_LOG ("P_STD_buffer_size : %d", res->P_STD_buffer_size);
data += 2;
length -= 2;
}
/* jump if we don't have a PES 2nd extension */
if (!(flags & 0x01))
goto stuffing_byte;
/* Extension flag 2 */
if (G_UNLIKELY (length < 1))
goto need_more_data;
val8 = *data++;
length -= 1;
if (!(val8 & 0x80))
goto bad_extension_marker_2;
res->extension_field_length = val8 & 0x7f;
/* Skip empty extensions */
if (G_UNLIKELY (res->extension_field_length == 0))
goto stuffing_byte;
if (G_UNLIKELY (length < res->extension_field_length))
goto need_more_data;
flags = *data++;
res->extension_field_length -= 1;
if (!(flags & 0x80)) {
/* Only valid if stream_id_extension_flag == 0x0 */
res->stream_id_extension = flags;
GST_LOG ("stream_id_extension : 0x%02x", res->stream_id_extension);
} else if (!(flags & 0x01)) {
/* Skip broken streams (that use stream_id_extension with highest bit set
* for example ...) */
if (G_UNLIKELY (res->extension_field_length < 5))
goto stuffing_byte;
GST_LOG ("TREF field present");
data += 5;
res->extension_field_length -= 5;
}
/* Extension field data */
if (res->extension_field_length) {
res->stream_id_extension_data = data;
GST_MEMDUMP ("stream_id_extension_data",
res->stream_id_extension_data, res->extension_field_length);
}
stuffing_byte:
/* Go to the expected data start position */
data = origdata + res->header_size;
length = origlength - res->header_size;
done_parsing:
GST_DEBUG ("origlength:%" G_GSIZE_FORMAT ", length:%" G_GSIZE_FORMAT,
origlength, length);
res->header_size = origlength - length;
ret = PES_PARSING_OK;
return ret;
/* Errors */
need_more_data:
GST_DEBUG ("Not enough data to parse PES header");
return ret;
bad_start_code:
GST_WARNING ("Wrong packet start code 0x%x != 0x000001xx", val32);
return PES_PARSING_BAD;
bad_marker_1:
GST_WARNING ("Wrong '0x10' marker before PES_scrambling_control (0x%02x)",
val8);
return PES_PARSING_BAD;
bad_PTS_value:
GST_WARNING ("bad PTS value");
return PES_PARSING_BAD;
bad_DTS_value:
GST_WARNING ("bad DTS value");
return PES_PARSING_BAD;
bad_ESCR_value:
GST_WARNING ("bad ESCR value");
return PES_PARSING_BAD;
bad_ES_rate:
GST_WARNING ("Invalid ES_rate markers 0x%0x", val32);
return PES_PARSING_BAD;
bad_original_copy_info_marker:
GST_WARNING ("Invalid original_copy_info marker bit: 0x%0x", val8);
return PES_PARSING_BAD;
bad_sequence_marker1:
GST_WARNING ("Invalid program_packet_sequence_counter marker 0x%0x", val8);
return PES_PARSING_BAD;
bad_sequence_marker2:
GST_WARNING ("Invalid program_packet_sequence_counter marker 0x%0x", val8);
return PES_PARSING_BAD;
bad_P_STD_marker:
GST_WARNING ("Invalid P-STD_buffer marker 0x%0x", val8);
return PES_PARSING_BAD;
bad_extension_marker_2:
GST_WARNING ("Invalid extension_field_2 marker 0x%0x", val8);
return PES_PARSING_BAD;
}
void
init_pes_parser (void)
{
GST_DEBUG_CATEGORY_INIT (pes_parser_debug, "pesparser", 0, "MPEG PES parser");
}
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