media/filters/ffmpeg_h264_to_annex_b_bitstream_converter.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "media/filters/ffmpeg_h264_to_annex_b_bitstream_converter.h"
   6
   7 #include "base/logging.h"
   8 #include "media/ffmpeg/ffmpeg_common.h"
   9 #include "media/formats/mp4/box_definitions.h"
  10
  11 namespace media {
  12
  13 FFmpegH264ToAnnexBBitstreamConverter::FFmpegH264ToAnnexBBitstreamConverter(
  14     AVCodecContext* stream_codec_context)
  15     : configuration_processed_(false),
  16       stream_codec_context_(stream_codec_context) {
  17   CHECK(stream_codec_context_);
  18 }
  19
  20 FFmpegH264ToAnnexBBitstreamConverter::~FFmpegH264ToAnnexBBitstreamConverter() {}
  21
  22 bool FFmpegH264ToAnnexBBitstreamConverter::ConvertPacket(AVPacket* packet) {
  23   scoped_ptr<mp4::AVCDecoderConfigurationRecord> avc_config;
  24
  25   if (packet == NULL || !packet->data)
  26     return false;
  27
  28   // Calculate the needed output buffer size.
  29   if (!configuration_processed_) {
  30     if (!stream_codec_context_->extradata ||
  31         stream_codec_context_->extradata_size <= 0)
  32       return false;
  33
  34     avc_config.reset(new mp4::AVCDecoderConfigurationRecord());
  35
  36     if (!converter_.ParseConfiguration(
  37             stream_codec_context_->extradata,
  38             stream_codec_context_->extradata_size,
  39             avc_config.get())) {
  40       return false;
  41     }
  42   }
  43
  44   uint32 output_packet_size = converter_.CalculateNeededOutputBufferSize(
  45       packet->data, packet->size, avc_config.get());
  46
  47   if (output_packet_size == 0)
  48     return false;  // Invalid input packet.
  49
  50   // Allocate new packet for the output.
  51   AVPacket dest_packet;
  52   if (av_new_packet(&dest_packet, output_packet_size) != 0)
  53     return false;  // Memory allocation failure.
  54
  55   // This is a bit tricky: since the interface does not allow us to replace
  56   // the pointer of the old packet with a new one, we will initially copy the
  57   // metadata from old packet to new bigger packet.
  58   av_packet_copy_props(&dest_packet, packet);
  59
  60   // Proceed with the conversion of the actual in-band NAL units, leave room
  61   // for configuration in the beginning.
  62   uint32 io_size = dest_packet.size;
  63   if (!converter_.ConvertNalUnitStreamToByteStream(
  64           packet->data, packet->size,
  65           avc_config.get(),
  66           dest_packet.data, &io_size)) {
  67     return false;
  68   }
  69
  70   if (avc_config)
  71     configuration_processed_ = true;
  72
  73   // At the end we must destroy the old packet.
  74   av_free_packet(packet);
  75   *packet = dest_packet;  // Finally, replace the values in the input packet.
  76
  77   return true;
  78 }
  79
  80 }  // namespace media