Line data    Source code

       1             : /* This Source Code Form is subject to the terms of the Mozilla Public
       2             :  * License, v. 2.0. If a copy of the MPL was not distributed with this
       3             :  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
       4             : 
       5             : #include "mp4_demuxer/Adts.h"
       6             : #include "MediaData.h"
       7             : #include "mozilla/Array.h"
       8             : #include "mozilla/ArrayUtils.h"
       9             : #include "nsAutoPtr.h"
      10             : 
      11             : using namespace mozilla;
      12             : 
      13             : namespace mp4_demuxer
      14             : {
      15             : 
      16             : int8_t
      17           0 : Adts::GetFrequencyIndex(uint32_t aSamplesPerSecond)
      18             : {
      19             :   static const uint32_t freq_lookup[] = { 96000, 88200, 64000, 48000, 44100,
      20             :                                           32000, 24000, 22050, 16000, 12000,
      21             :                                           11025, 8000,  7350,  0};
      22             : 
      23           0 :   int8_t i = 0;
      24           0 :   while (freq_lookup[i] && aSamplesPerSecond < freq_lookup[i]) {
      25           0 :     i++;
      26             :   }
      27             : 
      28           0 :   if (!freq_lookup[i]) {
      29           0 :     return -1;
      30             :   }
      31             : 
      32           0 :   return i;
      33             : }
      34             : 
      35             : bool
      36           0 : Adts::ConvertSample(uint16_t aChannelCount, int8_t aFrequencyIndex,
      37             :                     int8_t aProfile, MediaRawData* aSample)
      38             : {
      39             :   static const int kADTSHeaderSize = 7;
      40             : 
      41           0 :   size_t newSize = aSample->Size() + kADTSHeaderSize;
      42             : 
      43             :   // ADTS header uses 13 bits for packet size.
      44           0 :   if (newSize >= (1 << 13) || aChannelCount > 15 ||
      45           0 :       aFrequencyIndex < 0 || aProfile < 1 || aProfile > 4) {
      46           0 :     return false;
      47             :   }
      48             : 
      49           0 :   Array<uint8_t, kADTSHeaderSize> header;
      50           0 :   header[0] = 0xff;
      51           0 :   header[1] = 0xf1;
      52           0 :   header[2] =
      53           0 :     ((aProfile - 1) << 6) + (aFrequencyIndex << 2) + (aChannelCount >> 2);
      54           0 :   header[3] = ((aChannelCount & 0x3) << 6) + (newSize >> 11);
      55           0 :   header[4] = (newSize & 0x7ff) >> 3;
      56           0 :   header[5] = ((newSize & 7) << 5) + 0x1f;
      57           0 :   header[6] = 0xfc;
      58             : 
      59           0 :   nsAutoPtr<MediaRawDataWriter> writer(aSample->CreateWriter());
      60           0 :   if (!writer->Prepend(&header[0], ArrayLength(header))) {
      61           0 :     return false;
      62             :   }
      63             : 
      64           0 :   if (aSample->mCrypto.mValid) {
      65           0 :     if (aSample->mCrypto.mPlainSizes.Length() == 0) {
      66           0 :       writer->mCrypto.mPlainSizes.AppendElement(kADTSHeaderSize);
      67           0 :       writer->mCrypto.mEncryptedSizes.AppendElement(aSample->Size() - kADTSHeaderSize);
      68             :     } else {
      69           0 :       writer->mCrypto.mPlainSizes[0] += kADTSHeaderSize;
      70             :     }
      71             :   }
      72             : 
      73           0 :   return true;
      74             : }
      75             : }