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- /*
- * Copyright (c) 2016, Alliance for Open Media. All rights reserved
- *
- * This source code is subject to the terms of the BSD 2 Clause License and
- * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
- * was not distributed with this source code in the LICENSE file, you can
- * obtain it at www.aomedia.org/license/software. If the Alliance for Open
- * Media Patent License 1.0 was not distributed with this source code in the
- * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
- */
- #include "common/webmdec.h"
- #include <cassert>
- #include <cstring>
- #include <cstdio>
- #include "third_party/libwebm/mkvparser/mkvparser.h"
- #include "third_party/libwebm/mkvparser/mkvreader.h"
- namespace {
- void reset(struct WebmInputContext *const webm_ctx) {
- if (webm_ctx->reader != NULL) {
- mkvparser::MkvReader *const reader =
- reinterpret_cast<mkvparser::MkvReader *>(webm_ctx->reader);
- delete reader;
- }
- if (webm_ctx->segment != NULL) {
- mkvparser::Segment *const segment =
- reinterpret_cast<mkvparser::Segment *>(webm_ctx->segment);
- delete segment;
- }
- if (webm_ctx->buffer != NULL) {
- delete[] webm_ctx->buffer;
- }
- webm_ctx->reader = NULL;
- webm_ctx->segment = NULL;
- webm_ctx->buffer = NULL;
- webm_ctx->cluster = NULL;
- webm_ctx->block_entry = NULL;
- webm_ctx->block = NULL;
- webm_ctx->block_frame_index = 0;
- webm_ctx->video_track_index = 0;
- webm_ctx->timestamp_ns = 0;
- webm_ctx->is_key_frame = false;
- }
- void get_first_cluster(struct WebmInputContext *const webm_ctx) {
- mkvparser::Segment *const segment =
- reinterpret_cast<mkvparser::Segment *>(webm_ctx->segment);
- const mkvparser::Cluster *const cluster = segment->GetFirst();
- webm_ctx->cluster = cluster;
- }
- void rewind_and_reset(struct WebmInputContext *const webm_ctx,
- struct AvxInputContext *const aom_ctx) {
- rewind(aom_ctx->file);
- reset(webm_ctx);
- }
- } // namespace
- int file_is_webm(struct WebmInputContext *webm_ctx,
- struct AvxInputContext *aom_ctx) {
- mkvparser::MkvReader *const reader = new mkvparser::MkvReader(aom_ctx->file);
- webm_ctx->reader = reader;
- webm_ctx->reached_eos = 0;
- mkvparser::EBMLHeader header;
- long long pos = 0;
- if (header.Parse(reader, pos) < 0) {
- rewind_and_reset(webm_ctx, aom_ctx);
- return 0;
- }
- mkvparser::Segment *segment;
- if (mkvparser::Segment::CreateInstance(reader, pos, segment)) {
- rewind_and_reset(webm_ctx, aom_ctx);
- return 0;
- }
- webm_ctx->segment = segment;
- if (segment->Load() < 0) {
- rewind_and_reset(webm_ctx, aom_ctx);
- return 0;
- }
- const mkvparser::Tracks *const tracks = segment->GetTracks();
- const mkvparser::VideoTrack *video_track = NULL;
- for (unsigned long i = 0; i < tracks->GetTracksCount(); ++i) {
- const mkvparser::Track *const track = tracks->GetTrackByIndex(i);
- if (track->GetType() == mkvparser::Track::kVideo) {
- video_track = static_cast<const mkvparser::VideoTrack *>(track);
- webm_ctx->video_track_index = static_cast<int>(track->GetNumber());
- break;
- }
- }
- if (video_track == NULL || video_track->GetCodecId() == NULL) {
- rewind_and_reset(webm_ctx, aom_ctx);
- return 0;
- }
- if (!strncmp(video_track->GetCodecId(), "V_AV1", 5)) {
- aom_ctx->fourcc = AV1_FOURCC;
- } else {
- rewind_and_reset(webm_ctx, aom_ctx);
- return 0;
- }
- aom_ctx->framerate.denominator = 0;
- aom_ctx->framerate.numerator = 0;
- aom_ctx->width = static_cast<uint32_t>(video_track->GetWidth());
- aom_ctx->height = static_cast<uint32_t>(video_track->GetHeight());
- get_first_cluster(webm_ctx);
- return 1;
- }
- int webm_read_frame(struct WebmInputContext *webm_ctx, uint8_t **buffer,
- size_t *bytes_read, size_t *buffer_size) {
- assert(webm_ctx->buffer == *buffer);
- // This check is needed for frame parallel decoding, in which case this
- // function could be called even after it has reached end of input stream.
- if (webm_ctx->reached_eos) {
- return 1;
- }
- mkvparser::Segment *const segment =
- reinterpret_cast<mkvparser::Segment *>(webm_ctx->segment);
- const mkvparser::Cluster *cluster =
- reinterpret_cast<const mkvparser::Cluster *>(webm_ctx->cluster);
- const mkvparser::Block *block =
- reinterpret_cast<const mkvparser::Block *>(webm_ctx->block);
- const mkvparser::BlockEntry *block_entry =
- reinterpret_cast<const mkvparser::BlockEntry *>(webm_ctx->block_entry);
- bool block_entry_eos = false;
- do {
- long status = 0;
- bool get_new_block = false;
- if (block_entry == NULL && !block_entry_eos) {
- status = cluster->GetFirst(block_entry);
- get_new_block = true;
- } else if (block_entry_eos || block_entry->EOS()) {
- cluster = segment->GetNext(cluster);
- if (cluster == NULL || cluster->EOS()) {
- *bytes_read = 0;
- webm_ctx->reached_eos = 1;
- return 1;
- }
- status = cluster->GetFirst(block_entry);
- block_entry_eos = false;
- get_new_block = true;
- } else if (block == NULL ||
- webm_ctx->block_frame_index == block->GetFrameCount() ||
- block->GetTrackNumber() != webm_ctx->video_track_index) {
- status = cluster->GetNext(block_entry, block_entry);
- if (block_entry == NULL || block_entry->EOS()) {
- block_entry_eos = true;
- continue;
- }
- get_new_block = true;
- }
- if (status || block_entry == NULL) {
- return -1;
- }
- if (get_new_block) {
- block = block_entry->GetBlock();
- if (block == NULL) return -1;
- webm_ctx->block_frame_index = 0;
- }
- } while (block_entry_eos ||
- block->GetTrackNumber() != webm_ctx->video_track_index);
- webm_ctx->cluster = cluster;
- webm_ctx->block_entry = block_entry;
- webm_ctx->block = block;
- const mkvparser::Block::Frame &frame =
- block->GetFrame(webm_ctx->block_frame_index);
- ++webm_ctx->block_frame_index;
- if (frame.len > static_cast<long>(*buffer_size)) {
- delete[] * buffer;
- *buffer = new uint8_t[frame.len];
- webm_ctx->buffer = *buffer;
- if (*buffer == NULL) {
- return -1;
- }
- *buffer_size = frame.len;
- }
- *bytes_read = frame.len;
- webm_ctx->timestamp_ns = block->GetTime(cluster);
- webm_ctx->is_key_frame = block->IsKey();
- mkvparser::MkvReader *const reader =
- reinterpret_cast<mkvparser::MkvReader *>(webm_ctx->reader);
- return frame.Read(reader, *buffer) ? -1 : 0;
- }
- // Calculate the greatest common divisor between two numbers.
- static int gcd(int a, int b) {
- int remainder;
- while (b > 0) {
- remainder = a % b;
- a = b;
- b = remainder;
- }
- return a;
- }
- int webm_guess_framerate(struct WebmInputContext *webm_ctx,
- struct AvxInputContext *aom_ctx) {
- uint32_t i = 0;
- uint8_t *buffer = NULL;
- size_t buffer_size = 0;
- size_t bytes_read = 0;
- assert(webm_ctx->buffer == NULL);
- while (webm_ctx->timestamp_ns < 1000000000 && i < 50) {
- if (webm_read_frame(webm_ctx, &buffer, &bytes_read, &buffer_size)) {
- break;
- }
- ++i;
- }
- aom_ctx->framerate.numerator = (i - 1) * 1000000;
- aom_ctx->framerate.denominator =
- static_cast<int>(webm_ctx->timestamp_ns / 1000);
- // Fraction might be represented in large numbers, like 49000000/980000
- // for 50fps. Simplify as much as possible.
- int g = gcd(aom_ctx->framerate.numerator, aom_ctx->framerate.denominator);
- if (g != 0) {
- aom_ctx->framerate.numerator /= g;
- aom_ctx->framerate.denominator /= g;
- }
- delete[] buffer;
- webm_ctx->buffer = NULL;
- get_first_cluster(webm_ctx);
- webm_ctx->block = NULL;
- webm_ctx->block_entry = NULL;
- webm_ctx->block_frame_index = 0;
- webm_ctx->timestamp_ns = 0;
- webm_ctx->reached_eos = 0;
- return 0;
- }
- void webm_free(struct WebmInputContext *webm_ctx) { reset(webm_ctx); }
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