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Diffstat (limited to 'media/mp2t/ts_section_pes.cc')
| -rw-r--r-- | media/mp2t/ts_section_pes.cc | 312 |
1 files changed, 0 insertions, 312 deletions
diff --git a/media/mp2t/ts_section_pes.cc b/media/mp2t/ts_section_pes.cc deleted file mode 100644 index 6ff0bf1..0000000 --- a/media/mp2t/ts_section_pes.cc +++ /dev/null @@ -1,312 +0,0 @@ -// Copyright 2013 The Chromium Authors. All rights reserved. -// Use of this source code is governed by a BSD-style license that can be -// found in the LICENSE file. - -#include "media/mp2t/ts_section_pes.h" - -#include "base/logging.h" -#include "base/strings/string_number_conversions.h" -#include "media/base/bit_reader.h" -#include "media/base/buffers.h" -#include "media/mp2t/es_parser.h" -#include "media/mp2t/mp2t_common.h" - -static const int kPesStartCode = 0x000001; - -// Given that |time| is coded using 33 bits, -// UnrollTimestamp returns the corresponding unrolled timestamp. -// The unrolled timestamp is defined by: -// |time| + k * (2 ^ 33) -// where k is estimated so that the unrolled timestamp -// is as close as possible to |previous_unrolled_time|. -static int64 UnrollTimestamp(int64 previous_unrolled_time, int64 time) { - // Mpeg2 TS timestamps have an accuracy of 33 bits. - const int nbits = 33; - - // |timestamp| has a precision of |nbits| - // so make sure the highest bits are set to 0. - DCHECK_EQ((time >> nbits), 0); - - // Consider 3 possibilities to estimate the missing high bits of |time|. - int64 previous_unrolled_time_high = - (previous_unrolled_time >> nbits); - int64 time0 = ((previous_unrolled_time_high - 1) << nbits) | time; - int64 time1 = ((previous_unrolled_time_high + 0) << nbits) | time; - int64 time2 = ((previous_unrolled_time_high + 1) << nbits) | time; - - // Select the min absolute difference with the current time - // so as to ensure time continuity. - int64 diff0 = time0 - previous_unrolled_time; - int64 diff1 = time1 - previous_unrolled_time; - int64 diff2 = time2 - previous_unrolled_time; - if (diff0 < 0) - diff0 = -diff0; - if (diff1 < 0) - diff1 = -diff1; - if (diff2 < 0) - diff2 = -diff2; - - int64 unrolled_time; - int64 min_diff; - if (diff1 < diff0) { - unrolled_time = time1; - min_diff = diff1; - } else { - unrolled_time = time0; - min_diff = diff0; - } - if (diff2 < min_diff) - unrolled_time = time2; - - return unrolled_time; -} - -static bool IsTimestampSectionValid(int64 timestamp_section) { - // |pts_section| has 40 bits: - // - starting with either '0010' or '0011' or '0001' - // - and ending with a marker bit. - // See ITU H.222 standard - PES section. - - // Verify that all the marker bits are set to one. - return ((timestamp_section & 0x1) != 0) && - ((timestamp_section & 0x10000) != 0) && - ((timestamp_section & 0x100000000) != 0); -} - -static int64 ConvertTimestampSectionToTimestamp(int64 timestamp_section) { - return (((timestamp_section >> 33) & 0x7) << 30) | - (((timestamp_section >> 17) & 0x7fff) << 15) | - (((timestamp_section >> 1) & 0x7fff) << 0); -} - -namespace media { -namespace mp2t { - -TsSectionPes::TsSectionPes(scoped_ptr<EsParser> es_parser) - : es_parser_(es_parser.release()), - wait_for_pusi_(true), - previous_pts_valid_(false), - previous_pts_(0), - previous_dts_valid_(false), - previous_dts_(0) { - DCHECK(es_parser_); -} - -TsSectionPes::~TsSectionPes() { -} - -bool TsSectionPes::Parse(bool payload_unit_start_indicator, - const uint8* buf, int size) { - // Ignore partial PES. - if (wait_for_pusi_ && !payload_unit_start_indicator) - return true; - - bool parse_result = true; - if (payload_unit_start_indicator) { - // Try emitting a packet since we might have a pending PES packet - // with an undefined size. - // In this case, a unit is emitted when the next unit is coming. - int raw_pes_size; - const uint8* raw_pes; - pes_byte_queue_.Peek(&raw_pes, &raw_pes_size); - if (raw_pes_size > 0) - parse_result = Emit(true); - - // Reset the state. - ResetPesState(); - - // Update the state. - wait_for_pusi_ = false; - } - - // Add the data to the parser state. - if (size > 0) - pes_byte_queue_.Push(buf, size); - - // Try emitting the current PES packet. - return (parse_result && Emit(false)); -} - -void TsSectionPes::Flush() { - // Try emitting a packet since we might have a pending PES packet - // with an undefined size. - Emit(true); - - // Flush the underlying ES parser. - es_parser_->Flush(); -} - -void TsSectionPes::Reset() { - ResetPesState(); - - previous_pts_valid_ = false; - previous_pts_ = 0; - previous_dts_valid_ = false; - previous_dts_ = 0; - - es_parser_->Reset(); -} - -bool TsSectionPes::Emit(bool emit_for_unknown_size) { - int raw_pes_size; - const uint8* raw_pes; - pes_byte_queue_.Peek(&raw_pes, &raw_pes_size); - - // A PES should be at least 6 bytes. - // Wait for more data to come if not enough bytes. - if (raw_pes_size < 6) - return true; - - // Check whether we have enough data to start parsing. - int pes_packet_length = - (static_cast<int>(raw_pes[4]) << 8) | - (static_cast<int>(raw_pes[5])); - if ((pes_packet_length == 0 && !emit_for_unknown_size) || - (pes_packet_length != 0 && raw_pes_size < pes_packet_length + 6)) { - // Wait for more data to come either because: - // - there are not enough bytes, - // - or the PES size is unknown and the "force emit" flag is not set. - // (PES size might be unknown for video PES packet). - return true; - } - DVLOG(LOG_LEVEL_PES) << "pes_packet_length=" << pes_packet_length; - - // Parse the packet. - bool parse_result = ParseInternal(raw_pes, raw_pes_size); - - // Reset the state. - ResetPesState(); - - return parse_result; -} - -bool TsSectionPes::ParseInternal(const uint8* raw_pes, int raw_pes_size) { - BitReader bit_reader(raw_pes, raw_pes_size); - - // Read up to the pes_packet_length (6 bytes). - int packet_start_code_prefix; - int stream_id; - int pes_packet_length; - RCHECK(bit_reader.ReadBits(24, &packet_start_code_prefix)); - RCHECK(bit_reader.ReadBits(8, &stream_id)); - RCHECK(bit_reader.ReadBits(16, &pes_packet_length)); - - RCHECK(packet_start_code_prefix == kPesStartCode); - DVLOG(LOG_LEVEL_PES) << "stream_id=" << std::hex << stream_id << std::dec; - if (pes_packet_length == 0) - pes_packet_length = bit_reader.bits_available() / 8; - - // Ignore the PES for unknown stream IDs. - // See ITU H.222 Table 2-22 "Stream_id assignments" - bool is_audio_stream_id = ((stream_id & 0xe0) == 0xc0); - bool is_video_stream_id = ((stream_id & 0xf0) == 0xe0); - if (!is_audio_stream_id && !is_video_stream_id) - return true; - - // Read up to "pes_header_data_length". - int dummy_2; - int PES_scrambling_control; - bool PES_priority; - bool data_alignment_indicator; - bool copyright; - bool original_or_copy; - int pts_dts_flags; - bool escr_flag; - bool es_rate_flag; - bool dsm_trick_mode_flag; - bool additional_copy_info_flag; - bool pes_crc_flag; - bool pes_extension_flag; - int pes_header_data_length; - RCHECK(bit_reader.ReadBits(2, &dummy_2)); - RCHECK(dummy_2 == 0x2); - RCHECK(bit_reader.ReadBits(2, &PES_scrambling_control)); - RCHECK(bit_reader.ReadBits(1, &PES_priority)); - RCHECK(bit_reader.ReadBits(1, &data_alignment_indicator)); - RCHECK(bit_reader.ReadBits(1, ©right)); - RCHECK(bit_reader.ReadBits(1, &original_or_copy)); - RCHECK(bit_reader.ReadBits(2, &pts_dts_flags)); - RCHECK(bit_reader.ReadBits(1, &escr_flag)); - RCHECK(bit_reader.ReadBits(1, &es_rate_flag)); - RCHECK(bit_reader.ReadBits(1, &dsm_trick_mode_flag)); - RCHECK(bit_reader.ReadBits(1, &additional_copy_info_flag)); - RCHECK(bit_reader.ReadBits(1, &pes_crc_flag)); - RCHECK(bit_reader.ReadBits(1, &pes_extension_flag)); - RCHECK(bit_reader.ReadBits(8, &pes_header_data_length)); - int pes_header_start_size = bit_reader.bits_available() / 8; - - // Compute the size and the offset of the ES payload. - // "6" for the 6 bytes read before and including |pes_packet_length|. - // "3" for the 3 bytes read before and including |pes_header_data_length|. - int es_size = pes_packet_length - 3 - pes_header_data_length; - int es_offset = 6 + 3 + pes_header_data_length; - RCHECK(es_size >= 0); - RCHECK(es_offset + es_size <= raw_pes_size); - - // Read the timing information section. - bool is_pts_valid = false; - bool is_dts_valid = false; - int64 pts_section = 0; - int64 dts_section = 0; - if (pts_dts_flags == 0x2) { - RCHECK(bit_reader.ReadBits(40, &pts_section)); - RCHECK((((pts_section >> 36) & 0xf) == 0x2) && - IsTimestampSectionValid(pts_section)); - is_pts_valid = true; - } - if (pts_dts_flags == 0x3) { - RCHECK(bit_reader.ReadBits(40, &pts_section)); - RCHECK(bit_reader.ReadBits(40, &dts_section)); - RCHECK((((pts_section >> 36) & 0xf) == 0x3) && - IsTimestampSectionValid(pts_section)); - RCHECK((((dts_section >> 36) & 0xf) == 0x1) && - IsTimestampSectionValid(dts_section)); - is_pts_valid = true; - is_dts_valid = true; - } - - // Convert and unroll the timestamps. - base::TimeDelta media_pts(kNoTimestamp()); - base::TimeDelta media_dts(kNoTimestamp()); - if (is_pts_valid) { - int64 pts = ConvertTimestampSectionToTimestamp(pts_section); - if (previous_pts_valid_) - pts = UnrollTimestamp(previous_pts_, pts); - previous_pts_ = pts; - previous_pts_valid_ = true; - media_pts = base::TimeDelta::FromMicroseconds((1000 * pts) / 90); - } - if (is_dts_valid) { - int64 dts = ConvertTimestampSectionToTimestamp(dts_section); - if (previous_dts_valid_) - dts = UnrollTimestamp(previous_dts_, dts); - previous_dts_ = dts; - previous_dts_valid_ = true; - media_dts = base::TimeDelta::FromMicroseconds((1000 * dts) / 90); - } - - // Discard the rest of the PES packet header. - // TODO(damienv): check if some info of the PES packet header are useful. - DCHECK_EQ(bit_reader.bits_available() % 8, 0); - int pes_header_remaining_size = pes_header_data_length - - (pes_header_start_size - bit_reader.bits_available() / 8); - RCHECK(pes_header_remaining_size >= 0); - - // Read the PES packet. - DVLOG(LOG_LEVEL_PES) - << "Emit a reassembled PES:" - << " size=" << es_size - << " pts=" << media_pts.InMilliseconds() - << " dts=" << media_dts.InMilliseconds() - << " data_alignment_indicator=" << data_alignment_indicator; - return es_parser_->Parse(&raw_pes[es_offset], es_size, media_pts, media_dts); -} - -void TsSectionPes::ResetPesState() { - pes_byte_queue_.Reset(); - wait_for_pusi_ = true; -} - -} // namespace mp2t -} // namespace media - |