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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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