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// 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 <stddef.h>
#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_t* stream, off_t stream_size) {
std::vector<SubsampleEntry> subsamples;
SetEncryptedStream(stream, stream_size, subsamples);
}
void H265Parser::SetEncryptedStream(
const uint8_t* 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_t* start = stream;
const uint8_t* stream_end = stream_ + bytes_left_;
for (size_t i = 0; i < subsamples.size() && start < stream_end; ++i) {
start += subsamples[i].clear_bytes;
const uint8_t* 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_t* 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
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