ref: ce13498b2acccadbd1961e9c52ef2a9b778ca8c2
dir: /webmdec.cc/
/* * Copyright (c) 2013 The WebM project authors. All Rights Reserved. * * Use of this source code is governed by a BSD-style license * that can be found in the LICENSE file in the root of the source * tree. An additional intellectual property rights grant can be found * in the file PATENTS. All contributing project authors may * be found in the AUTHORS file in the root of the source tree. */ #include "./webmdec.h" #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 VpxInputContext *const vpx_ctx) { rewind(vpx_ctx->file); reset(webm_ctx); } } // namespace int file_is_webm(struct WebmInputContext *webm_ctx, struct VpxInputContext *vpx_ctx) { mkvparser::MkvReader *const reader = new mkvparser::MkvReader(vpx_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, vpx_ctx); return 0; } mkvparser::Segment *segment; if (mkvparser::Segment::CreateInstance(reader, pos, segment)) { rewind_and_reset(webm_ctx, vpx_ctx); return 0; } webm_ctx->segment = segment; if (segment->Load() < 0) { rewind_and_reset(webm_ctx, vpx_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, vpx_ctx); return 0; } if (!strncmp(video_track->GetCodecId(), "V_VP8", 5)) { vpx_ctx->fourcc = VP8_FOURCC; } else if (!strncmp(video_track->GetCodecId(), "V_VP9", 5)) { vpx_ctx->fourcc = VP9_FOURCC; } else { rewind_and_reset(webm_ctx, vpx_ctx); return 0; } vpx_ctx->framerate.denominator = 0; vpx_ctx->framerate.numerator = 0; vpx_ctx->width = static_cast<uint32_t>(video_track->GetWidth()); vpx_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 *buffer_size) { // 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()) { *buffer_size = 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]; if (*buffer == NULL) { return -1; } webm_ctx->buffer = *buffer; } *buffer_size = 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; } int webm_guess_framerate(struct WebmInputContext *webm_ctx, struct VpxInputContext *vpx_ctx) { uint32_t i = 0; uint8_t *buffer = NULL; size_t buffer_size = 0; while (webm_ctx->timestamp_ns < 1000000000 && i < 50) { if (webm_read_frame(webm_ctx, &buffer, &buffer_size)) { break; } ++i; } vpx_ctx->framerate.numerator = (i - 1) * 1000000; vpx_ctx->framerate.denominator = static_cast<int>(webm_ctx->timestamp_ns / 1000); delete[] buffer; 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); }