111 lines
3.5 KiB
C++
111 lines
3.5 KiB
C++
// Copyright (c) 2015 The WebM project authors. All Rights Reserved.
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//
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// Use of this source code is governed by a BSD-style license
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// that can be found in the LICENSE file in the root of the source
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// tree. An additional intellectual property rights grant can be found
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// in the file PATENTS. All contributing project authors may
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// be found in the AUTHORS file in the root of the source tree.
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#include "common/libwebm_util.h"
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#include <cassert>
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#include <cstdint>
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#include <cstdio>
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#include <limits>
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namespace libwebm {
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std::int64_t NanosecondsTo90KhzTicks(std::int64_t nanoseconds) {
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const double pts_seconds = nanoseconds / kNanosecondsPerSecond;
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return static_cast<std::int64_t>(pts_seconds * 90000);
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}
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std::int64_t Khz90TicksToNanoseconds(std::int64_t ticks) {
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const double seconds = ticks / 90000.0;
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return static_cast<std::int64_t>(seconds * kNanosecondsPerSecond);
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}
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bool ParseVP9SuperFrameIndex(const std::uint8_t* frame,
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std::size_t frame_length, Ranges* frame_ranges,
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bool* error) {
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if (frame == nullptr || frame_length == 0 || frame_ranges == nullptr ||
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error == nullptr) {
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return false;
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}
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bool parse_ok = false;
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const std::uint8_t marker = frame[frame_length - 1];
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const std::uint32_t kHasSuperFrameIndexMask = 0xe0;
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const std::uint32_t kSuperFrameMarker = 0xc0;
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const std::uint32_t kLengthFieldSizeMask = 0x3;
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if ((marker & kHasSuperFrameIndexMask) == kSuperFrameMarker) {
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const std::uint32_t kFrameCountMask = 0x7;
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const int num_frames = (marker & kFrameCountMask) + 1;
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const int length_field_size = ((marker >> 3) & kLengthFieldSizeMask) + 1;
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const std::size_t index_length = 2 + length_field_size * num_frames;
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if (frame_length < index_length) {
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std::fprintf(stderr,
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"VP9ParseSuperFrameIndex: Invalid superframe index size.\n");
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*error = true;
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return false;
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}
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// Consume the super frame index. Note: it's at the end of the super frame.
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const std::size_t length = frame_length - index_length;
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if (length >= index_length &&
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frame[frame_length - index_length] == marker) {
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// Found a valid superframe index.
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const std::uint8_t* byte = frame + length + 1;
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std::size_t frame_offset = 0;
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for (int i = 0; i < num_frames; ++i) {
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std::uint32_t child_frame_length = 0;
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for (int j = 0; j < length_field_size; ++j) {
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child_frame_length |= (*byte++) << (j * 8);
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}
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if (length - frame_offset < child_frame_length) {
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std::fprintf(stderr,
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"ParseVP9SuperFrameIndex: Invalid superframe, sub frame "
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"larger than entire frame.\n");
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*error = true;
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return false;
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}
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frame_ranges->push_back(Range(frame_offset, child_frame_length));
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frame_offset += child_frame_length;
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}
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if (static_cast<int>(frame_ranges->size()) != num_frames) {
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std::fprintf(stderr, "VP9Parse: superframe index parse failed.\n");
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*error = true;
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return false;
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}
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parse_ok = true;
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} else {
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std::fprintf(stderr, "VP9Parse: Invalid superframe index.\n");
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*error = true;
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}
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}
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return parse_ok;
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}
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bool WriteUint8(std::uint8_t val, std::FILE* fileptr) {
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if (fileptr == nullptr)
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return false;
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return (std::fputc(val, fileptr) == val);
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}
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std::uint16_t ReadUint16(const std::uint8_t* buf) {
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if (buf == nullptr)
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return 0;
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return ((buf[0] << 8) | buf[1]);
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}
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} // namespace libwebm
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