Support HLS MPEG2 TS with SAMPLE-AES encryption.

media/formats/mp2t/es_parser_adts.cc

 // Copyright 2014 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/formats/mp2t/es_parser_adts.h"
 
 #include <stddef.h>
 
 #include <vector>
 
@@ skipping 11 matching lines @@
 #include "media/formats/mpeg/adts_header_parser.h"
 
 namespace media {
 
 static int ExtractAdtsFrameSize(const uint8_t* adts_header) {
   return ((static_cast<int>(adts_header[5]) >> 5) |
           (static_cast<int>(adts_header[4]) << 3) |
           ((static_cast<int>(adts_header[3]) & 0x3) << 11));
 }
 
+static int AdtsHeaderSize(const uint8_t* adts_header) {
+  // protection absent bit: set to 1 if there is no CRC and 0 if there is CRC
+  return (adts_header[1] & 0x1) ? kADTSHeaderSizeNoCrc : kADTSHeaderSizeWithCrc;
+}
+
 // Return true if buf corresponds to an ADTS syncword.
 // |buf| size must be at least 2.
 static bool isAdtsSyncWord(const uint8_t* buf) {
   // The first 12 bits must be 1.
   // The layer field (2 bits) must be set to 0.
   return (buf[0] == 0xff) && ((buf[1] & 0xf6) == 0xf0);
 }
 
 namespace mp2t {
 
 struct EsParserAdts::AdtsFrame {
   // Pointer to the ES data.
   const uint8_t* data;
 
   // Frame size;
   int size;
+  int header_size;
 
   // Frame offset in the ES queue.
   int64_t queue_offset;
 };
 
 bool EsParserAdts::LookForAdtsFrame(AdtsFrame* adts_frame) {
   int es_size;
   const uint8_t* es;
   es_queue_->Peek(&es, &es_size);
 
   int max_offset = es_size - kADTSHeaderMinSize;
   if (max_offset <= 0)
     return false;
 
   for (int offset = 0; offset < max_offset; offset++) {
     const uint8_t* cur_buf = &es[offset];
     if (!isAdtsSyncWord(cur_buf))
       continue;
 
     int frame_size = ExtractAdtsFrameSize(cur_buf);
     if (frame_size < kADTSHeaderMinSize) {
       // Too short to be an ADTS frame.
       continue;
     }
+    int header_size = AdtsHeaderSize(cur_buf);
 
     int remaining_size = es_size - offset;
     if (remaining_size < frame_size) {
       // Not a full frame: will resume when we have more data.
       es_queue_->Pop(offset);
       return false;
     }
 
     // Check whether there is another frame
     // |size| apart from the current one.
     if (remaining_size >= frame_size + 2 &&
         !isAdtsSyncWord(&cur_buf[frame_size])) {
       continue;
     }
 
     es_queue_->Pop(offset);
     es_queue_->Peek(&adts_frame->data, &es_size);
     adts_frame->queue_offset = es_queue_->head();
     adts_frame->size = frame_size;
+    adts_frame->header_size = header_size;
     DVLOG(LOG_LEVEL_ES)
         << "ADTS syncword @ pos=" << adts_frame->queue_offset
         << " frame_size=" << adts_frame->size;
     DVLOG(LOG_LEVEL_ES)
         << "ADTS header: "
         << base::HexEncode(adts_frame->data, kADTSHeaderMinSize);
     return true;
   }
 
   es_queue_->Pop(max_offset);
   return false;
 }
 
 void EsParserAdts::SkipAdtsFrame(const AdtsFrame& adts_frame) {
   DCHECK_EQ(adts_frame.queue_offset, es_queue_->head());
   es_queue_->Pop(adts_frame.size);
 }
 
-EsParserAdts::EsParserAdts(
-    const NewAudioConfigCB& new_audio_config_cb,
-    const EmitBufferCB& emit_buffer_cb,
-    bool sbr_in_mimetype)
-  : new_audio_config_cb_(new_audio_config_cb),
-    emit_buffer_cb_(emit_buffer_cb),
-    sbr_in_mimetype_(sbr_in_mimetype) {
+EsParserAdts::EsParserAdts(const NewAudioConfigCB& new_audio_config_cb,
+                           const EmitBufferCB& emit_buffer_cb,
+                           bool sbr_in_mimetype)
+    : new_audio_config_cb_(new_audio_config_cb),
+      emit_buffer_cb_(emit_buffer_cb),
+#if BUILDFLAG(ENABLE_HLS_SAMPLE_AES)
+      get_decrypt_config_cb_(),
+      use_hls_sample_aes_(false),
+#endif
+      sbr_in_mimetype_(sbr_in_mimetype) {
 }
 
+#if BUILDFLAG(ENABLE_HLS_SAMPLE_AES)
+EsParserAdts::EsParserAdts(const NewAudioConfigCB& new_audio_config_cb,
+                           const EmitBufferCB& emit_buffer_cb,
+                           const GetDecryptConfigCB& get_decrypt_config_cb,
+                           bool use_hls_sample_aes,
+                           bool sbr_in_mimetype)
+    : new_audio_config_cb_(new_audio_config_cb),
+      emit_buffer_cb_(emit_buffer_cb),
+      get_decrypt_config_cb_(get_decrypt_config_cb),
+      use_hls_sample_aes_(use_hls_sample_aes),
+      sbr_in_mimetype_(sbr_in_mimetype) {}
+#endif
+
 EsParserAdts::~EsParserAdts() {
 }
 
+#if BUILDFLAG(ENABLE_HLS_SAMPLE_AES)
+void EsParserAdts::CalculateSubsamplesForAdtsFrame(
+    const AdtsFrame& adts_frame,
+    std::vector<SubsampleEntry>* subsamples) {
+  DCHECK(subsamples);
+  subsamples->clear();
+  int data_size = adts_frame.size - adts_frame.header_size;
+  int residue = data_size % 16;
+  int clear_bytes = adts_frame.header_size;
+  int encrypted_bytes = 0;
+  if (data_size <= 16) {
+    clear_bytes += data_size;
+    residue = 0;
+  } else {
+    clear_bytes += 16;
+    encrypted_bytes = adts_frame.size - clear_bytes - residue;
+  }
+  SubsampleEntry subsample(clear_bytes, encrypted_bytes);
+  subsamples->push_back(subsample);
+  if (residue) {
+    subsample.clear_bytes = residue;
+    subsample.cypher_bytes = 0;
+    subsamples->push_back(subsample);
+  }
+}
+#endif
+
 bool EsParserAdts::ParseFromEsQueue() {
   // Look for every ADTS frame in the ES buffer.
   AdtsFrame adts_frame;
   while (LookForAdtsFrame(&adts_frame)) {
     // Update the audio configuration if needed.
     DCHECK_GE(adts_frame.size, kADTSHeaderMinSize);
     if (!UpdateAudioConfiguration(adts_frame.data))
       return false;
 
     // Get the PTS & the duration of this access unit.
@@ skipping 19 matching lines @@
     scoped_refptr<StreamParserBuffer> stream_parser_buffer =
         StreamParserBuffer::CopyFrom(
             adts_frame.data,
             adts_frame.size,
             is_key_frame,
             DemuxerStream::AUDIO, 0);
     stream_parser_buffer->set_timestamp(current_pts);
     stream_parser_buffer->SetDecodeTimestamp(
         DecodeTimestamp::FromPresentationTime(current_pts));
     stream_parser_buffer->set_duration(frame_duration);
+#if BUILDFLAG(ENABLE_HLS_SAMPLE_AES)
+    if (use_hls_sample_aes_) {
+      const DecryptConfig* base_decrypt_config = get_decrypt_config_cb_.Run();
+      RCHECK(base_decrypt_config);
+      std::vector<SubsampleEntry> subsamples;
+      CalculateSubsamplesForAdtsFrame(adts_frame, &subsamples);
+      scoped_ptr<DecryptConfig> decrypt_config(
+          new DecryptConfig(base_decrypt_config->key_id(),
+                            base_decrypt_config->iv(), subsamples));
+      stream_parser_buffer->set_decrypt_config(std::move(decrypt_config));
+    }
+#endif
     emit_buffer_cb_.Run(stream_parser_buffer);
 
     // Update the PTS of the next frame.
     audio_timestamp_helper_->AddFrames(kSamplesPerAACFrame);
 
     // Skip the current frame.
     SkipAdtsFrame(adts_frame);
   }
 
   return true;
 }
 
 void EsParserAdts::Flush() {
 }
 
 void EsParserAdts::ResetInternal() {
   last_audio_decoder_config_ = AudioDecoderConfig();
 }
 
 bool EsParserAdts::UpdateAudioConfiguration(const uint8_t* adts_header) {
   AudioDecoderConfig audio_decoder_config;
-  if (!ParseAdtsHeader(adts_header, sbr_in_mimetype_, &audio_decoder_config))
+  EncryptionScheme scheme = Unencrypted();
+#if BUILDFLAG(ENABLE_HLS_SAMPLE_AES)
+  if (use_hls_sample_aes_) {
+    scheme = EncryptionScheme(EncryptionScheme::CIPHER_MODE_AES_CBC,
+                              EncryptionScheme::Pattern());
+  }
+#endif
+  if (!ParseAdtsHeader(adts_header, sbr_in_mimetype_, scheme,
+                       &audio_decoder_config))
     return false;
 
   if (!audio_decoder_config.Matches(last_audio_decoder_config_)) {
     DVLOG(1) << "Sampling frequency: "
              << audio_decoder_config.samples_per_second();
     DVLOG(1) << "Channel layout: "
              << ChannelLayoutToString(audio_decoder_config.channel_layout());
     // Reset the timestamp helper to use a new time scale.
     if (audio_timestamp_helper_ &&
         audio_timestamp_helper_->base_timestamp() != kNoTimestamp()) {
       base::TimeDelta base_timestamp = audio_timestamp_helper_->GetTimestamp();
       audio_timestamp_helper_.reset(
           new AudioTimestampHelper(audio_decoder_config.samples_per_second()));
       audio_timestamp_helper_->SetBaseTimestamp(base_timestamp);
     } else {
       audio_timestamp_helper_.reset(
           new AudioTimestampHelper(audio_decoder_config.samples_per_second()));
     }
     // Audio config notification.
     last_audio_decoder_config_ = audio_decoder_config;
     new_audio_config_cb_.Run(audio_decoder_config);
   }
 
   return true;
 }
 
 }  // namespace mp2t
 }  // namespace media