230 строки
6.9 KiB
C++
230 строки
6.9 KiB
C++
/*
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* Copyright (c) 2013 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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*/
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#include "./webmdec.h"
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#include <cstring>
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#include <cstdio>
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#include "third_party/libwebm/mkvparser.hpp"
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#include "third_party/libwebm/mkvreader.hpp"
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namespace {
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void reset(struct WebmInputContext *const webm_ctx) {
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if (webm_ctx->reader != NULL) {
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mkvparser::MkvReader *const reader =
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reinterpret_cast<mkvparser::MkvReader*>(webm_ctx->reader);
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delete reader;
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}
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if (webm_ctx->segment != NULL) {
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mkvparser::Segment *const segment =
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reinterpret_cast<mkvparser::Segment*>(webm_ctx->segment);
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delete segment;
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}
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if (webm_ctx->buffer != NULL) {
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delete[] webm_ctx->buffer;
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}
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webm_ctx->reader = NULL;
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webm_ctx->segment = NULL;
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webm_ctx->buffer = NULL;
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webm_ctx->cluster = NULL;
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webm_ctx->block_entry = NULL;
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webm_ctx->block = NULL;
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webm_ctx->block_frame_index = 0;
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webm_ctx->video_track_index = 0;
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webm_ctx->timestamp_ns = 0;
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webm_ctx->is_key_frame = false;
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}
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void get_first_cluster(struct WebmInputContext *const webm_ctx) {
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mkvparser::Segment *const segment =
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reinterpret_cast<mkvparser::Segment*>(webm_ctx->segment);
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const mkvparser::Cluster *const cluster = segment->GetFirst();
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webm_ctx->cluster = cluster;
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}
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void rewind_and_reset(struct WebmInputContext *const webm_ctx,
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struct VpxInputContext *const vpx_ctx) {
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rewind(vpx_ctx->file);
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reset(webm_ctx);
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}
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} // namespace
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int file_is_webm(struct WebmInputContext *webm_ctx,
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struct VpxInputContext *vpx_ctx) {
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mkvparser::MkvReader *const reader = new mkvparser::MkvReader(vpx_ctx->file);
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webm_ctx->reader = reader;
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webm_ctx->reached_eos = 0;
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mkvparser::EBMLHeader header;
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long long pos = 0;
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if (header.Parse(reader, pos) < 0) {
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rewind_and_reset(webm_ctx, vpx_ctx);
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return 0;
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}
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mkvparser::Segment* segment;
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if (mkvparser::Segment::CreateInstance(reader, pos, segment)) {
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rewind_and_reset(webm_ctx, vpx_ctx);
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return 0;
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}
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webm_ctx->segment = segment;
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if (segment->Load() < 0) {
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rewind_and_reset(webm_ctx, vpx_ctx);
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return 0;
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}
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const mkvparser::Tracks *const tracks = segment->GetTracks();
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const mkvparser::VideoTrack* video_track = NULL;
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for (unsigned long i = 0; i < tracks->GetTracksCount(); ++i) {
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const mkvparser::Track* const track = tracks->GetTrackByIndex(i);
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if (track->GetType() == mkvparser::Track::kVideo) {
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video_track = static_cast<const mkvparser::VideoTrack*>(track);
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webm_ctx->video_track_index = track->GetNumber();
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break;
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}
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}
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if (video_track == NULL) {
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rewind_and_reset(webm_ctx, vpx_ctx);
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return 0;
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}
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if (!strncmp(video_track->GetCodecId(), "V_VP8", 5)) {
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vpx_ctx->fourcc = VP8_FOURCC;
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} else if (!strncmp(video_track->GetCodecId(), "V_VP9", 5)) {
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vpx_ctx->fourcc = VP9_FOURCC;
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} else {
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rewind_and_reset(webm_ctx, vpx_ctx);
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return 0;
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}
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vpx_ctx->framerate.denominator = 0;
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vpx_ctx->framerate.numerator = 0;
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vpx_ctx->width = static_cast<uint32_t>(video_track->GetWidth());
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vpx_ctx->height = static_cast<uint32_t>(video_track->GetHeight());
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get_first_cluster(webm_ctx);
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return 1;
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}
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int webm_read_frame(struct WebmInputContext *webm_ctx,
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uint8_t **buffer,
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size_t *bytes_in_buffer,
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size_t *buffer_size) {
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// This check is needed for frame parallel decoding, in which case this
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// function could be called even after it has reached end of input stream.
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if (webm_ctx->reached_eos) {
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return 1;
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}
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mkvparser::Segment *const segment =
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reinterpret_cast<mkvparser::Segment*>(webm_ctx->segment);
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const mkvparser::Cluster* cluster =
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reinterpret_cast<const mkvparser::Cluster*>(webm_ctx->cluster);
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const mkvparser::Block *block =
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reinterpret_cast<const mkvparser::Block*>(webm_ctx->block);
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const mkvparser::BlockEntry *block_entry =
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reinterpret_cast<const mkvparser::BlockEntry*>(webm_ctx->block_entry);
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bool block_entry_eos = false;
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do {
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long status = 0;
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bool get_new_block = false;
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if (block_entry == NULL && !block_entry_eos) {
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status = cluster->GetFirst(block_entry);
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get_new_block = true;
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} else if (block_entry_eos || block_entry->EOS()) {
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cluster = segment->GetNext(cluster);
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if (cluster == NULL || cluster->EOS()) {
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*bytes_in_buffer = 0;
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webm_ctx->reached_eos = 1;
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return 1;
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}
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status = cluster->GetFirst(block_entry);
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block_entry_eos = false;
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get_new_block = true;
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} else if (block == NULL ||
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webm_ctx->block_frame_index == block->GetFrameCount() ||
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block->GetTrackNumber() != webm_ctx->video_track_index) {
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status = cluster->GetNext(block_entry, block_entry);
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if (block_entry == NULL || block_entry->EOS()) {
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block_entry_eos = true;
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continue;
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}
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get_new_block = true;
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}
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if (status) {
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return -1;
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}
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if (get_new_block) {
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block = block_entry->GetBlock();
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webm_ctx->block_frame_index = 0;
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}
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} while (block->GetTrackNumber() != webm_ctx->video_track_index ||
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block_entry_eos);
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webm_ctx->cluster = cluster;
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webm_ctx->block_entry = block_entry;
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webm_ctx->block = block;
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const mkvparser::Block::Frame& frame =
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block->GetFrame(webm_ctx->block_frame_index);
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++webm_ctx->block_frame_index;
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if (frame.len > static_cast<long>(*buffer_size)) {
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delete[] *buffer;
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*buffer = new uint8_t[frame.len];
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if (*buffer == NULL) {
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return -1;
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}
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*buffer_size = frame.len;
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webm_ctx->buffer = *buffer;
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}
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*bytes_in_buffer = frame.len;
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webm_ctx->timestamp_ns = block->GetTime(cluster);
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webm_ctx->is_key_frame = block->IsKey();
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mkvparser::MkvReader *const reader =
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reinterpret_cast<mkvparser::MkvReader*>(webm_ctx->reader);
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return frame.Read(reader, *buffer) ? -1 : 0;
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}
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int webm_guess_framerate(struct WebmInputContext *webm_ctx,
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struct VpxInputContext *vpx_ctx) {
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uint32_t i = 0;
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uint8_t *buffer = NULL;
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size_t bytes_in_buffer = 0;
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size_t buffer_size = 0;
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while (webm_ctx->timestamp_ns < 1000000000 && i < 50) {
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if (webm_read_frame(webm_ctx, &buffer, &bytes_in_buffer, &buffer_size)) {
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break;
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}
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++i;
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}
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vpx_ctx->framerate.numerator = (i - 1) * 1000000;
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vpx_ctx->framerate.denominator =
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static_cast<int>(webm_ctx->timestamp_ns / 1000);
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delete[] buffer;
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get_first_cluster(webm_ctx);
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webm_ctx->block = NULL;
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webm_ctx->block_entry = NULL;
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webm_ctx->block_frame_index = 0;
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webm_ctx->timestamp_ns = 0;
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webm_ctx->reached_eos = 0;
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return 0;
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}
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void webm_free(struct WebmInputContext *webm_ctx) {
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reset(webm_ctx);
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}
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