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gstreamer/gst/mpegtsdemux/pesparse.c
Edward Hervey d0e8427b4e pesparse: Fix stuffing byte handling 
We in fact get the size of the header (including stuffing bytes), therefore
use that instead of trying to skip 0xff bytes ourselves since some media
streams do start with 0xff (like mpeg audio's initial 0xfff).
2011-07-20 19:19:13 +02:00

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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., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, 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.
* @offset: Offset in @data to the data to parse. If #PES_PARSING_OK, offset to
* first byte of data after the header.
*
* 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,
gint * offset)
{
PESParsingResult ret = PES_PARSING_NEED_MORE;
gsize origlength = length;
const guint8 *origdata = data;
guint32 val32;
guint8 val8, flags;
g_return_val_if_fail (res != NULL, PES_PARSING_BAD);
g_return_val_if_fail (offset != NULL, PES_PARSING_BAD);
g_return_val_if_fail (*offset < length, PES_PARSING_BAD);
data += *offset;
length -= *offset;
/* 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);
/* 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_DEBUG ("PES_flag 0x%02x", flags);
/* 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))
goto bad_PTS_DTS_flags;
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 >> 1;
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 0x%02x", flags);
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++;
/* GRMBL, this is most often wrong */
if (G_UNLIKELY ((val8 & 0x80) != 0x80))
goto bad_sequence_marker1;
res->program_packet_sequence_counter = val8 * 0x70;
GST_LOG ("program_packet_sequence_counter %d",
res->program_packet_sequence_counter);
val8 = *data++;
/* GRMBL, this is most often wrong */
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;
}
if (flags & 0x01) {
/* 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;
if (G_UNLIKELY (length < res->extension_field_length + 1))
goto need_more_data;
GST_LOG ("extension_field_length : %" G_GSSIZE_FORMAT,
res->extension_field_length);
if (res->extension_field_length) {
flags = *data++;
/* Only valid if stream_id_extension_flag == 0x0 */
if (!(flags & 0x80)) {
res->stream_id_extension = flags & 0x7f;
GST_LOG ("stream_id_extension : 0x%02x", res->stream_id_extension);
res->stream_id_extension_data = data;
GST_MEMDUMP ("stream_id_extension_data",
res->stream_id_extension_data, res->extension_field_length);
} else
GST_WARNING ("What are we meant to do ??");
data += res->extension_field_length;
}
length -= res->extension_field_length + 1;
}
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_GSSIZE_FORMAT ", length:%" G_GSSIZE_FORMAT,
origlength, length);
res->header_size = origlength - length;
*offset += res->header_size;
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_DTS_flags:
GST_WARNING ("Invalid '0x01' PTS_DTS_flags");
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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