diff options
Diffstat (limited to 'chromium/media/filters/h265_parser.cc')
-rw-r--r-- | chromium/media/filters/h265_parser.cc | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/chromium/media/filters/h265_parser.cc b/chromium/media/filters/h265_parser.cc new file mode 100644 index 00000000000..30a8233c143 --- /dev/null +++ b/chromium/media/filters/h265_parser.cc @@ -0,0 +1,159 @@ +// Copyright 2015 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 "base/logging.h" +#include "base/memory/scoped_ptr.h" +#include "base/stl_util.h" + +#include "media/base/decrypt_config.h" +#include "media/filters/h265_parser.h" + +namespace media { + +#define READ_BITS_OR_RETURN(num_bits, out) \ + do { \ + int _out; \ + if (!br_.ReadBits(num_bits, &_out)) { \ + DVLOG(1) \ + << "Error in stream: unexpected EOS while trying to read " #out; \ + return kInvalidStream; \ + } \ + *out = _out; \ + } while (0) + +#define TRUE_OR_RETURN(a) \ + do { \ + if (!(a)) { \ + DVLOG(1) << "Error in stream: invalid value, expected " << #a; \ + return kInvalidStream; \ + } \ + } while (0) + +H265NALU::H265NALU() { + memset(this, 0, sizeof(*this)); +} + +H265Parser::H265Parser() { + Reset(); +} + +H265Parser::~H265Parser() { +} + +void H265Parser::Reset() { + stream_ = NULL; + bytes_left_ = 0; + encrypted_ranges_.clear(); +} + +void H265Parser::SetStream(const uint8* stream, off_t stream_size) { + std::vector<SubsampleEntry> subsamples; + SetEncryptedStream(stream, stream_size, subsamples); +} + +void H265Parser::SetEncryptedStream( + const uint8* stream, off_t stream_size, + const std::vector<SubsampleEntry>& subsamples) { + DCHECK(stream); + DCHECK_GT(stream_size, 0); + + stream_ = stream; + bytes_left_ = stream_size; + + encrypted_ranges_.clear(); + const uint8* start = stream; + const uint8* stream_end = stream_ + bytes_left_; + for (size_t i = 0; i < subsamples.size() && start < stream_end; ++i) { + start += subsamples[i].clear_bytes; + + const uint8* end = std::min(start + subsamples[i].cypher_bytes, stream_end); + encrypted_ranges_.Add(start, end); + start = end; + } +} + +bool H265Parser::LocateNALU(off_t* nalu_size, off_t* start_code_size) { + // Find the start code of next NALU. + off_t nalu_start_off = 0; + off_t annexb_start_code_size = 0; + + if (!H264Parser::FindStartCodeInClearRanges(stream_, bytes_left_, + encrypted_ranges_, + &nalu_start_off, + &annexb_start_code_size)) { + DVLOG(4) << "Could not find start code, end of stream?"; + return false; + } + + // Move the stream to the beginning of the NALU (pointing at the start code). + stream_ += nalu_start_off; + bytes_left_ -= nalu_start_off; + + const uint8* nalu_data = stream_ + annexb_start_code_size; + off_t max_nalu_data_size = bytes_left_ - annexb_start_code_size; + if (max_nalu_data_size <= 0) { + DVLOG(3) << "End of stream"; + return false; + } + + // Find the start code of next NALU; + // if successful, |nalu_size_without_start_code| is the number of bytes from + // after previous start code to before this one; + // if next start code is not found, it is still a valid NALU since there + // are some bytes left after the first start code: all the remaining bytes + // belong to the current NALU. + off_t next_start_code_size = 0; + off_t nalu_size_without_start_code = 0; + if (!H264Parser::FindStartCodeInClearRanges(nalu_data, max_nalu_data_size, + encrypted_ranges_, + &nalu_size_without_start_code, + &next_start_code_size)) { + nalu_size_without_start_code = max_nalu_data_size; + } + *nalu_size = nalu_size_without_start_code + annexb_start_code_size; + *start_code_size = annexb_start_code_size; + return true; +} + +H265Parser::Result H265Parser::AdvanceToNextNALU(H265NALU* nalu) { + off_t start_code_size; + off_t nalu_size_with_start_code; + if (!LocateNALU(&nalu_size_with_start_code, &start_code_size)) { + DVLOG(4) << "Could not find next NALU, bytes left in stream: " + << bytes_left_; + return kEOStream; + } + + nalu->data = stream_ + start_code_size; + nalu->size = nalu_size_with_start_code - start_code_size; + DVLOG(4) << "NALU found: size=" << nalu_size_with_start_code; + + // Initialize bit reader at the start of found NALU. + if (!br_.Initialize(nalu->data, nalu->size)) + return kEOStream; + + // Move parser state to after this NALU, so next time AdvanceToNextNALU + // is called, we will effectively be skipping it; + // other parsing functions will use the position saved + // in bit reader for parsing, so we don't have to remember it here. + stream_ += nalu_size_with_start_code; + bytes_left_ -= nalu_size_with_start_code; + + // Read NALU header, skip the forbidden_zero_bit, but check for it. + int data; + READ_BITS_OR_RETURN(1, &data); + TRUE_OR_RETURN(data == 0); + + READ_BITS_OR_RETURN(6, &nalu->nal_unit_type); + READ_BITS_OR_RETURN(6, &nalu->nuh_layer_id); + READ_BITS_OR_RETURN(3, &nalu->nuh_temporal_id_plus1); + + DVLOG(4) << "NALU type: " << static_cast<int>(nalu->nal_unit_type) + << " at: " << reinterpret_cast<const void*>(nalu->data) + << " size: " << nalu->size; + + return kOk; +} + +} // namespace media |