shaka-packager/media/webm/webm_tracks_parser.cc

// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "media/webm/webm_tracks_parser.h"

#include "base/logging.h"
#include "base/strings/string_util.h"
#include "media/base/buffers.h"
#include "media/webm/webm_constants.h"
#include "media/webm/webm_content_encodings.h"

namespace media {

static TextKind CodecIdToTextKind(const std::string& codec_id) {
  if (codec_id == kWebMCodecSubtitles)
    return kTextSubtitles;

  if (codec_id == kWebMCodecCaptions)
    return kTextCaptions;

  if (codec_id == kWebMCodecDescriptions)
    return kTextDescriptions;

  if (codec_id == kWebMCodecMetadata)
    return kTextMetadata;

  return kTextNone;
}

WebMTracksParser::WebMTracksParser(const LogCB& log_cb, bool ignore_text_tracks)
    : track_type_(-1),
      track_num_(-1),
      audio_track_num_(-1),
      video_track_num_(-1),
      ignore_text_tracks_(ignore_text_tracks),
      log_cb_(log_cb),
      audio_client_(log_cb),
      video_client_(log_cb) {
}

WebMTracksParser::~WebMTracksParser() {}

int WebMTracksParser::Parse(const uint8* buf, int size) {
  track_type_ =-1;
  track_num_ = -1;
  track_name_.clear();
  track_language_.clear();
  audio_track_num_ = -1;
  audio_decoder_config_ = AudioDecoderConfig();
  video_track_num_ = -1;
  video_decoder_config_ = VideoDecoderConfig();
  text_tracks_.clear();
  ignored_tracks_.clear();

  WebMListParser parser(kWebMIdTracks, this);
  int result = parser.Parse(buf, size);

  if (result <= 0)
    return result;

  // For now we do all or nothing parsing.
  return parser.IsParsingComplete() ? result : 0;
}

WebMParserClient* WebMTracksParser::OnListStart(int id) {
  if (id == kWebMIdContentEncodings) {
    DCHECK(!track_content_encodings_client_.get());
    track_content_encodings_client_.reset(
        new WebMContentEncodingsClient(log_cb_));
    return track_content_encodings_client_->OnListStart(id);
  }

  if (id == kWebMIdTrackEntry) {
    track_type_ = -1;
    track_num_ = -1;
    track_name_.clear();
    track_language_.clear();
    codec_id_ = "";
    codec_private_.clear();
    audio_client_.Reset();
    video_client_.Reset();
    return this;
  }

  if (id == kWebMIdAudio)
    return &audio_client_;

  if (id == kWebMIdVideo)
    return &video_client_;

  return this;
}

bool WebMTracksParser::OnListEnd(int id) {
  if (id == kWebMIdContentEncodings) {
    DCHECK(track_content_encodings_client_.get());
    return track_content_encodings_client_->OnListEnd(id);
  }

  if (id == kWebMIdTrackEntry) {
    if (track_type_ == -1 || track_num_ == -1) {
      MEDIA_LOG(log_cb_) << "Missing TrackEntry data for "
                         << " TrackType " << track_type_
                         << " TrackNum " << track_num_;
      return false;
    }

    if (track_type_ != kWebMTrackTypeAudio &&
        track_type_ != kWebMTrackTypeVideo &&
        track_type_ != kWebMTrackTypeSubtitlesOrCaptions &&
        track_type_ != kWebMTrackTypeDescriptionsOrMetadata) {
      MEDIA_LOG(log_cb_) << "Unexpected TrackType " << track_type_;
      return false;
    }

    TextKind text_track_kind = kTextNone;
    if (track_type_ == kWebMTrackTypeSubtitlesOrCaptions) {
      text_track_kind = CodecIdToTextKind(codec_id_);
      if (text_track_kind == kTextNone) {
        MEDIA_LOG(log_cb_) << "Missing TrackEntry CodecID"
                           << " TrackNum " << track_num_;
        return false;
      }

      if (text_track_kind != kTextSubtitles &&
          text_track_kind != kTextCaptions) {
        MEDIA_LOG(log_cb_) << "Wrong TrackEntry CodecID"
                           << " TrackNum " << track_num_;
        return false;
      }
    } else if (track_type_ == kWebMTrackTypeDescriptionsOrMetadata) {
      text_track_kind = CodecIdToTextKind(codec_id_);
      if (text_track_kind == kTextNone) {
        MEDIA_LOG(log_cb_) << "Missing TrackEntry CodecID"
                           << " TrackNum " << track_num_;
        return false;
      }

      if (text_track_kind != kTextDescriptions &&
          text_track_kind != kTextMetadata) {
        MEDIA_LOG(log_cb_) << "Wrong TrackEntry CodecID"
                           << " TrackNum " << track_num_;
        return false;
      }
    }

    std::string encryption_key_id;
    if (track_content_encodings_client_) {
      DCHECK(!track_content_encodings_client_->content_encodings().empty());
      // If we have multiple ContentEncoding in one track. Always choose the
      // key id in the first ContentEncoding as the key id of the track.
      encryption_key_id = track_content_encodings_client_->
          content_encodings()[0]->encryption_key_id();
    }

    if (track_type_ == kWebMTrackTypeAudio) {
      if (audio_track_num_ == -1) {
        audio_track_num_ = track_num_;
        audio_encryption_key_id_ = encryption_key_id;

        DCHECK(!audio_decoder_config_.IsValidConfig());
        if (!audio_client_.InitializeConfig(
                codec_id_, codec_private_, !audio_encryption_key_id_.empty(),
                &audio_decoder_config_)) {
          return false;
        }
      } else {
        MEDIA_LOG(log_cb_) << "Ignoring audio track " << track_num_;
        ignored_tracks_.insert(track_num_);
      }
    } else if (track_type_ == kWebMTrackTypeVideo) {
      if (video_track_num_ == -1) {
        video_track_num_ = track_num_;
        video_encryption_key_id_ = encryption_key_id;

        DCHECK(!video_decoder_config_.IsValidConfig());
        if (!video_client_.InitializeConfig(
                codec_id_, codec_private_, !video_encryption_key_id_.empty(),
                &video_decoder_config_)) {
          return false;
        }
      } else {
        MEDIA_LOG(log_cb_) << "Ignoring video track " << track_num_;
        ignored_tracks_.insert(track_num_);
      }
    } else if (track_type_ == kWebMTrackTypeSubtitlesOrCaptions ||
               track_type_ == kWebMTrackTypeDescriptionsOrMetadata) {
      if (ignore_text_tracks_) {
        MEDIA_LOG(log_cb_) << "Ignoring text track " << track_num_;
        ignored_tracks_.insert(track_num_);
      } else {
        TextTrackInfo& text_track_info = text_tracks_[track_num_];
        text_track_info.kind = text_track_kind;
        text_track_info.name = track_name_;
        text_track_info.language = track_language_;
      }
    } else {
      MEDIA_LOG(log_cb_) << "Unexpected TrackType " << track_type_;
      return false;
    }

    track_type_ = -1;
    track_num_ = -1;
    track_name_.clear();
    track_language_.clear();
    codec_id_ = "";
    codec_private_.clear();
    track_content_encodings_client_.reset();

    audio_client_.Reset();
    video_client_.Reset();
    return true;
  }

  return true;
}

bool WebMTracksParser::OnUInt(int id, int64 val) {
  int64* dst = NULL;

  switch (id) {
    case kWebMIdTrackNumber:
      dst = &track_num_;
      break;
    case kWebMIdTrackType:
      dst = &track_type_;
      break;
    default:
      return true;
  }

  if (*dst != -1) {
    MEDIA_LOG(log_cb_) << "Multiple values for id " << std::hex << id
                       << " specified";
    return false;
  }

  *dst = val;
  return true;
}

bool WebMTracksParser::OnFloat(int id, double val) {
  return true;
}

bool WebMTracksParser::OnBinary(int id, const uint8* data, int size) {
  if (id == kWebMIdCodecPrivate) {
    if (!codec_private_.empty()) {
      MEDIA_LOG(log_cb_) << "Multiple CodecPrivate fields in a track.";
      return false;
    }

    codec_private_.assign(data, data + size);
    return true;
  }
  return true;
}

bool WebMTracksParser::OnString(int id, const std::string& str) {
  if (id == kWebMIdCodecID) {
    if (!codec_id_.empty()) {
      MEDIA_LOG(log_cb_) << "Multiple CodecID fields in a track";
      return false;
    }

    codec_id_ = str;
    return true;
  }

  if (id == kWebMIdName) {
    track_name_ = str;
    return true;
  }

  if (id == kWebMIdLanguage) {
    track_language_ = str;
    return true;
  }

  return true;
}

}  // namespace media