diff options
Diffstat (limited to 'webmdec.cc')
| -rw-r--r-- | webmdec.cc | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/webmdec.cc b/webmdec.cc new file mode 100644 index 000000000..4383e8efd --- /dev/null +++ b/webmdec.cc @@ -0,0 +1,219 @@ +/* + * 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.hpp" +#include "third_party/libwebm/mkvreader.hpp" + +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; +} + +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; + + 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 = track->GetNumber(); + break; + } + } + + if (video_track == 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 *bytes_in_buffer, + size_t *buffer_size) { + 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_in_buffer = 0; + 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) { + return -1; + } + if (get_new_block) { + block = block_entry->GetBlock(); + webm_ctx->block_frame_index = 0; + } + } while (block->GetTrackNumber() != webm_ctx->video_track_index || + block_entry_eos); + + 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; + } + *buffer_size = frame.len; + webm_ctx->buffer = *buffer; + } + *bytes_in_buffer = frame.len; + webm_ctx->timestamp_ns = block->GetTime(cluster); + + 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 bytes_in_buffer = 0; + size_t buffer_size = 0; + while (webm_ctx->timestamp_ns < 1000000000 && i < 50) { + if (webm_read_frame(webm_ctx, &buffer, &bytes_in_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; + + return 0; +} + +void webm_free(struct WebmInputContext *webm_ctx) { + reset(webm_ctx); +} |