/* * gstmpegtssection.c - * Copyright (C) 2013 Edward Hervey * Copyright (C) 2011, Hewlett-Packard Development Company, L.P. * Copyright (C) 2007 Alessandro Decina * 2010 Edward Hervey * Author: Youness Alaoui , Collabora Ltd. * Author: Sebastian Dröge , Collabora Ltd. * Author: Edward Hervey , Collabora Ltd. * * Authors: * Alessandro Decina * Zaheer Abbas Merali * Edward Hervey * * This library is free softwagre; 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. */ #include #include #include "mpegts.h" #include "gstmpegts-private.h" /** * SECTION:gstmpegtssection * @short_description: Convenience library for using MPEG-TS sections * * For more details, refer to the ITU H.222.0 or ISO/IEC 13818-1 specifications * and other specifications mentionned in the documentation. */ /* * TODO * * * Check minimum size for section parsing in the various * gst_mpegts_section_get_() methods * * * Implement parsing code for * * BAT * * CAT * * TSDT */ GST_DEBUG_CATEGORY (gst_mpegts_debug); static GQuark QUARK_PAT; static GQuark QUARK_CAT; static GQuark QUARK_BAT; static GQuark QUARK_PMT; static GQuark QUARK_NIT; static GQuark QUARK_SDT; static GQuark QUARK_EIT; static GQuark QUARK_TDT; static GQuark QUARK_TOT; static GQuark QUARK_SECTION; static GType _gst_mpegts_section_type = 0; #define MPEG_TYPE_TS_SECTION (_gst_mpegts_section_type) GST_DEFINE_MINI_OBJECT_TYPE (GstMpegTsSection, gst_mpegts_section); static const guint32 crc_tab[256] = { 0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005, 0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd, 0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75, 0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd, 0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039, 0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5, 0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d, 0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49, 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95, 0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d, 0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072, 0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16, 0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca, 0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde, 0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02, 0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba, 0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692, 0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6, 0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a, 0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e, 0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2, 0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a, 0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637, 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb, 0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53, 0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b, 0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff, 0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623, 0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b, 0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f, 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3, 0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b, 0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3, 0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640, 0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c, 0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8, 0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24, 0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec, 0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654, 0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0, 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c, 0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18, 0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4, 0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c, 0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668, 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4 }; /* _calc_crc32 relicenced to LGPL from fluendo ts demuxer */ guint32 _calc_crc32 (const guint8 * data, guint datalen) { gint i; guint32 crc = 0xffffffff; for (i = 0; i < datalen; i++) { crc = (crc << 8) ^ crc_tab[((crc >> 24) ^ *data++) & 0xff]; } return crc; } /* * GENERIC MPEG-TS SECTION */ static void _gst_mpegts_section_free (GstMpegTsSection * section) { GST_DEBUG ("Freeing section type %d", section->section_type); if (section->cached_parsed && section->destroy_parsed) section->destroy_parsed (section->cached_parsed); if (section->data) g_free (section->data); g_slice_free (GstMpegTsSection, section); } static GstMpegTsSection * _gst_mpegts_section_copy (GstMpegTsSection * section) { GstMpegTsSection *copy; copy = g_slice_new0 (GstMpegTsSection); gst_mini_object_init (GST_MINI_OBJECT_CAST (copy), 0, MPEG_TYPE_TS_SECTION, (GstMiniObjectCopyFunction) _gst_mpegts_section_copy, NULL, (GstMiniObjectFreeFunction) _gst_mpegts_section_free); copy->section_type = section->section_type; copy->pid = section->pid; copy->table_id = section->table_id; copy->subtable_extension = section->subtable_extension; copy->version_number = section->version_number; copy->current_next_indicator = section->current_next_indicator; copy->section_number = section->section_number; copy->last_section_number = section->last_section_number; copy->crc = section->crc; copy->data = g_memdup (section->data, section->section_length); copy->section_length = section->section_length; /* Note: We do not copy the cached parsed item, it will be * reconstructed on that copy */ copy->cached_parsed = NULL; copy->offset = section->offset; copy->short_section = section->short_section; return copy; } /** * gst_message_parse_mpegts_section: * @message: a #GstMessage * * Returns the #GstMpegTsSection contained in a message. * * Returns: (transfer full): the contained #GstMpegTsSection, or %NULL. */ GstMpegTsSection * gst_message_parse_mpegts_section (GstMessage * message) { const GstStructure *st; GstMpegTsSection *section; if (message->type != GST_MESSAGE_ELEMENT) return NULL; st = gst_message_get_structure (message); /* FIXME : Add checks against know section names */ if (!gst_structure_id_get (st, QUARK_SECTION, GST_TYPE_MPEGTS_SECTION, §ion, NULL)) return NULL; return section; } /** * gst_message_new_mpegts_section: * @parent: (transfer none): The creator of the message * @section: (transfer none): The #GstMpegTsSection to put in a message * * Creates a new #GstMessage for a @GstMpegTsSection. * * Returns: (transfer full): The new #GstMessage to be posted, or %NULL if the * section is not valid. */ GstMessage * gst_message_new_mpegts_section (GstObject * parent, GstMpegTsSection * section) { GstMessage *msg; GstStructure *st; GQuark quark; switch (section->section_type) { case GST_MPEGTS_SECTION_PAT: quark = QUARK_PAT; break; case GST_MPEGTS_SECTION_PMT: quark = QUARK_PMT; break; case GST_MPEGTS_SECTION_CAT: quark = QUARK_CAT; break; case GST_MPEGTS_SECTION_EIT: quark = QUARK_EIT; break; case GST_MPEGTS_SECTION_BAT: quark = QUARK_BAT; break; case GST_MPEGTS_SECTION_NIT: quark = QUARK_NIT; break; case GST_MPEGTS_SECTION_SDT: quark = QUARK_SDT; break; case GST_MPEGTS_SECTION_TDT: quark = QUARK_TDT; break; case GST_MPEGTS_SECTION_TOT: quark = QUARK_TOT; break; default: GST_WARNING ("Creating message for unknown GstMpegTsSection"); quark = QUARK_SECTION; break; } st = gst_structure_new_id (quark, QUARK_SECTION, MPEG_TYPE_TS_SECTION, section, NULL); msg = gst_message_new_element (parent, st); return msg; } /* Program Association Table */ static GArray * _parse_pat (GstMpegTsSection * section) { GArray *pat; guint16 i = 0, nb_programs; GstMpegTsPatProgram *program; guint8 *data, *end; /* Skip already parsed data */ data = section->data + 8; /* stop at the CRC */ end = section->data + section->section_length; /* Initialize program list */ nb_programs = (end - 4 - data) / 4; pat = g_array_sized_new (FALSE, FALSE, sizeof (GstMpegTsPatProgram), nb_programs); while (data < end - 4) { program = &g_array_index (pat, GstMpegTsPatProgram, i); program->program_number = GST_READ_UINT16_BE (data); data += 2; program->network_or_program_map_PID = GST_READ_UINT16_BE (data) & 0x1FFF; data += 2; i++; } pat->len = nb_programs; if (data != end - 4) { GST_ERROR ("at the end of PAT data != end - 4"); g_array_unref (pat); return NULL; } return pat; } /** * gst_mpegts_section_get_pat: * @section: a #GstMpegTsSection of type %GST_MPEGTS_SECTION_PAT * * Parses a Program Association Table (ITU H.222.0, ISO/IEC 13818-1). * * Returns the array of #GstMpegTsPatProgram contained in the section. * * Note: The PAT "transport_id" field corresponds to the "subtable_extension" * field of the provided @section. * * Returns: (transfer container) (element-type GstMpegTsPatProgram): The * #GstMpegTsPatProgram contained in the section, or %NULL if an error * happened. Release with #g_ptr_array_unref when done. */ GArray * gst_mpegts_section_get_pat (GstMpegTsSection * section) { g_return_val_if_fail (section->section_type == GST_MPEGTS_SECTION_PAT, NULL); g_return_val_if_fail (section->cached_parsed || section->data, NULL); if (!section->cached_parsed) { if (G_UNLIKELY (_calc_crc32 (section->data, section->section_length) != 0)) goto bad_crc; section->cached_parsed = (gpointer) _parse_pat (section); section->destroy_parsed = (GDestroyNotify) g_array_unref; if (section->cached_parsed == NULL) goto parse_failure; } return g_array_ref ((GArray *) section->cached_parsed); bad_crc: { GST_WARNING ("Bad CRC on section"); return NULL; } parse_failure: { GST_WARNING ("Failure to parse section"); return NULL; } } /* Program Map Table */ static GstMpegTsPMTStream * _gst_mpegts_pmt_stream_copy (GstMpegTsPMTStream * pmt) { /* FIXME : IMPLEMENT */ return NULL; } static void _gst_mpegts_pmt_stream_free (GstMpegTsPMTStream * pmt) { g_array_unref (pmt->descriptors); g_slice_free (GstMpegTsPMTStream, pmt); } G_DEFINE_BOXED_TYPE (GstMpegTsPMTStream, gst_mpegts_pmt_stream, (GBoxedCopyFunc) _gst_mpegts_pmt_stream_copy, (GFreeFunc) _gst_mpegts_pmt_stream_free); static GstMpegTsPMT * _gst_mpegts_pmt_copy (GstMpegTsPMT * pmt) { /* FIXME : IMPLEMENT */ return NULL; } static void _gst_mpegts_pmt_free (GstMpegTsPMT * pmt) { g_array_unref (pmt->descriptors); g_ptr_array_unref (pmt->streams); g_slice_free (GstMpegTsPMT, pmt); } G_DEFINE_BOXED_TYPE (GstMpegTsPMT, gst_mpegts_pmt, (GBoxedCopyFunc) _gst_mpegts_pmt_copy, (GFreeFunc) _gst_mpegts_pmt_free); static GstMpegTsPMT * _parse_pmt (GstMpegTsSection * section) { GstMpegTsPMT *pmt = NULL; guint i = 0, allocated_streams = 8; guint8 *data, *end; guint program_info_length; guint stream_info_length; /* fixed header + CRC == 16 */ if (section->section_length < 16) { GST_WARNING ("PID %d invalid PMT size %d", section->pid, section->section_length); goto error; } pmt = g_slice_new0 (GstMpegTsPMT); data = section->data; end = data + section->section_length; GST_DEBUG ("Parsing %d Program Map Table", section->subtable_extension); /* Skip already parsed data */ data += 8; pmt->pcr_pid = GST_READ_UINT16_BE (data) & 0x1FFF; data += 2; program_info_length = GST_READ_UINT16_BE (data) & 0x0FFF; data += 2; /* check that the buffer is large enough to contain at least * program_info_length bytes + CRC */ if (program_info_length && (data + program_info_length + 4 > end)) { GST_WARNING ("PID %d invalid program info length %d left %d", section->pid, program_info_length, (gint) (end - data)); goto error; } pmt->descriptors = gst_mpegts_parse_descriptors (data, program_info_length); if (pmt->descriptors == NULL) goto error; data += program_info_length; pmt->streams = g_ptr_array_new_full (allocated_streams, (GDestroyNotify) _gst_mpegts_pmt_stream_free); /* parse entries, cycle until there's space for another entry (at least 5 * bytes) plus the CRC */ while (data <= end - 4 - 5) { GstMpegTsPMTStream *stream = g_slice_new0 (GstMpegTsPMTStream); g_ptr_array_add (pmt->streams, stream); stream->stream_type = *data++; GST_DEBUG ("[%d] Stream type 0x%02x found", i, stream->stream_type); stream->pid = GST_READ_UINT16_BE (data) & 0x1FFF; data += 2; stream_info_length = GST_READ_UINT16_BE (data) & 0x0FFF; data += 2; if (data + stream_info_length + 4 > end) { GST_WARNING ("PID %d invalid stream info length %d left %d", section->pid, stream_info_length, (gint) (end - data)); goto error; } stream->descriptors = gst_mpegts_parse_descriptors (data, stream_info_length); if (stream->descriptors == NULL) goto error; data += stream_info_length; i += 1; } g_assert (data == end - 4); return pmt; error: if (pmt) gst_mpegts_section_unref (pmt); return NULL; } /** * gst_mpegts_section_get_pmt: * @section: a #GstMpegTsSection of type %GST_MPEGTS_SECTION_PMT * * Returns the #GstMpegTsPMT contained in the @section. * * Returns: The #GstMpegTsPMT contained in the section, or %NULL if an error * happened. */ const GstMpegTsPMT * gst_mpegts_section_get_pmt (GstMpegTsSection * section) { g_return_val_if_fail (section->section_type == GST_MPEGTS_SECTION_PMT, NULL); g_return_val_if_fail (section->cached_parsed || section->data, NULL); if (!section->cached_parsed) { if (G_UNLIKELY (_calc_crc32 (section->data, section->section_length) != 0)) goto bad_crc; section->cached_parsed = (gpointer) _parse_pmt (section); section->destroy_parsed = (GDestroyNotify) _gst_mpegts_pmt_free; if (section->cached_parsed == NULL) goto parse_failure; } return (const GstMpegTsPMT *) section->cached_parsed; bad_crc: { GST_WARNING ("Bad CRC on section"); return NULL; } parse_failure: { GST_WARNING ("Failure to parse section"); return NULL; } } /* Conditional Access Table */ static GArray * _parse_cat (GstMpegTsSection * section) { guint8 *data; guint desc_len; /* Skip parts already parsed */ data = section->data + 8; /* descriptors */ desc_len = section->section_length - 4 - 8; return gst_mpegts_parse_descriptors (data, desc_len); } /** * gst_mpegts_section_get_cat: * @section: a #GstMpegTsSection of type %GST_MPEGTS_SECTION_CAT * * Returns the array of #GstMpegTsDescriptor contained in the Condtional * Access Table. * * Returns: (transfer container) (element-type GstMpegTsDescriptor): The * #GstMpegTsDescriptor contained in the section, or %NULL if an error * happened. Release with #g_array_unref when done. */ GArray * gst_mpegts_section_get_cat (GstMpegTsSection * section) { g_return_val_if_fail (section->section_type == GST_MPEGTS_SECTION_CAT, NULL); g_return_val_if_fail (section->cached_parsed || section->data, NULL); if (!section->cached_parsed) { section->cached_parsed = (gpointer) _parse_cat (section); section->destroy_parsed = (GDestroyNotify) g_array_unref; if (section->cached_parsed == NULL) goto parse_failure; } return g_array_ref ((GArray *) section->cached_parsed); parse_failure: { GST_WARNING ("Failure to parse section"); return NULL; } } /* Transport Stream Description Table (TSDT) */ /** * gst_mpegts_section_get_tsdt: * @section: a #GstMpegTsSection of type %GST_MPEGTS_SECTION_TSDT * * Returns the array of #GstMpegTsDescriptor contained in the section * * Returns: (transfer container) (element-type GstMpegTsDescriptor): The * #GstMpegTsDescriptor contained in the section, or %NULL if an error * happened. Release with #g_array_unref when done. */ GArray * gst_mpegts_section_get_tsdt (GstMpegTsSection * section) { g_return_val_if_fail (section->section_type == GST_MPEGTS_SECTION_TSDT, NULL); g_return_val_if_fail (section->cached_parsed || section->data, NULL); if (section->cached_parsed) return g_array_ref ((GArray *) section->cached_parsed); /* FIXME : parse TSDT */ return NULL; } /** * gst_mpegts_initialize: * * Initializes the MPEG-TS helper library. Must be called before any * usage. */ void gst_mpegts_initialize (void) { if (_gst_mpegts_section_type) return; GST_DEBUG_CATEGORY_INIT (gst_mpegts_debug, "mpegts", 0, "MPEG-TS helper library"); /* FIXME : Temporary hack to initialize section gtype */ _gst_mpegts_section_type = gst_mpegts_section_get_type (); QUARK_PAT = g_quark_from_string ("pat"); QUARK_CAT = g_quark_from_string ("cat"); QUARK_PMT = g_quark_from_string ("pmt"); QUARK_NIT = g_quark_from_string ("nit"); QUARK_BAT = g_quark_from_string ("bat"); QUARK_SDT = g_quark_from_string ("sdt"); QUARK_EIT = g_quark_from_string ("eit"); QUARK_TDT = g_quark_from_string ("tdt"); QUARK_TOT = g_quark_from_string ("tot"); QUARK_SECTION = g_quark_from_string ("section"); __initialize_descriptors (); } /* FIXME : Later on we might need to use more than just the table_id * to figure out which type of section this is. */ static GstMpegTsSectionType _identify_section (guint8 table_id) { switch (table_id) { case GST_MTS_TABLE_ID_PROGRAM_ASSOCIATION: return GST_MPEGTS_SECTION_PAT; case GST_MTS_TABLE_ID_CONDITIONAL_ACCESS: return GST_MPEGTS_SECTION_CAT; case GST_MTS_TABLE_ID_TS_PROGRAM_MAP: return GST_MPEGTS_SECTION_PMT; case GST_MTS_TABLE_ID_BOUQUET_ASSOCIATION: return GST_MPEGTS_SECTION_BAT; case GST_MTS_TABLE_ID_NETWORK_INFORMATION_ACTUAL_NETWORK: case GST_MTS_TABLE_ID_NETWORK_INFORMATION_OTHER_NETWORK: return GST_MPEGTS_SECTION_NIT; case GST_MTS_TABLE_ID_SERVICE_DESCRIPTION_ACTUAL_TS: case GST_MTS_TABLE_ID_SERVICE_DESCRIPTION_OTHER_TS: return GST_MPEGTS_SECTION_SDT; case GST_MTS_TABLE_ID_TIME_DATE: return GST_MPEGTS_SECTION_TDT; case GST_MTS_TABLE_ID_TIME_OFFSET: return GST_MPEGTS_SECTION_TOT; /* FIXME : FILL */ default: /* Handle ranges */ if (table_id >= GST_MTS_TABLE_ID_EVENT_INFORMATION_ACTUAL_TS_PRESENT && table_id <= GST_MTS_TABLE_ID_EVENT_INFORMATION_OTHER_TS_SCHEDULE_N) return GST_MPEGTS_SECTION_EIT; return GST_MPEGTS_SECTION_UNKNOWN; } } /** * gst_mpegts_section_new: * @pid: the PID to which this section belongs * @data: (transfer full): a pointer to the beginning of the section (i.e. the first byte * should contain the table_id field). * @data_size: size of the @data argument. * * Creates a new #GstMpegTsSection from the provided @data. * * Note: Ensuring @data is big enough to contain the full section is the * responsibility of the caller. If it is not big enough, %NULL will be * returned. * * Note: it is the responsibility of the caller to ensure @data does point * to the beginning of the section. * * Returns: (transfer full): A new #GstMpegTsSection if the data was valid, * else %NULL */ GstMpegTsSection * gst_mpegts_section_new (guint16 pid, guint8 * data, gsize data_size) { GstMpegTsSection *res = NULL; guint8 tmp; guint16 section_length; /* Check for length */ section_length = GST_READ_UINT16_BE (data + 1) & 0x0FFF; if (G_UNLIKELY (data_size < section_length + 3)) goto short_packet; res = g_slice_new0 (GstMpegTsSection); gst_mini_object_init (GST_MINI_OBJECT_CAST (res), 0, MPEG_TYPE_TS_SECTION, (GstMiniObjectCopyFunction) _gst_mpegts_section_copy, NULL, (GstMiniObjectFreeFunction) _gst_mpegts_section_free); res->pid = pid; res->data = data; /* table_id : 8 bit */ res->table_id = *data++; /* section_syntax_indicator : 1 bit * other_fields (reserved) : 3 bit*/ res->short_section = (*data & 0x80) == 0x00; /* section_length (already parsed) : 12 bit */ res->section_length = section_length + 3; if (!res->short_section) { /* CRC is after section_length (-4 for the size of the CRC) */ res->crc = GST_READ_UINT32_BE (res->data + res->section_length - 4); /* Skip to after section_length */ data += 2; /* subtable extension : 16 bit */ res->subtable_extension = GST_READ_UINT16_BE (data); data += 2; /* reserved : 2 bit * version_number : 5 bit * current_next_indicator : 1 bit */ tmp = *data++; res->version_number = tmp >> 1 & 0x1f; res->current_next_indicator = tmp & 0x01; /* section_number : 8 bit */ res->section_number = *data++; /* last_section_number : 8 bit */ res->last_section_number = *data; } res->section_type = _identify_section (res->table_id); return res; short_packet: { GST_WARNING ("PID 0x%04x section extends past provided data (got:%" G_GSIZE_FORMAT ", need:%d)", pid, data_size, section_length + 3); return NULL; } }