media/webm/chromeos/webm_encoder.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/webm/chromeos/webm_encoder.h"
   6
   7 #include "base/bind.h"
   8 #include "base/file_util.h"
   9 #include "base/logging.h"
  10 #include "base/memory/scoped_ptr.h"
  11 #include "libyuv/convert.h"
  12 #include "libyuv/video_common.h"
  13 #include "third_party/skia/include/core/SkBitmap.h"
  14
  15 extern "C" {
  16 // Getting the right degree of C compatibility has been a constant struggle.
  17 // - Stroustrup, C++ Report, 12(7), July/August 2000.
  18 #define private priv
  19 #include "third_party/libvpx/source/libvpx/libmkv/EbmlIDs.h"
  20 #include "third_party/libvpx/source/libvpx/libmkv/EbmlWriter.h"
  21 #undef private
  22 }
  23
  24 // Number of encoder threads to use.
  25 static const int kNumEncoderThreads = 2;
  26
  27 // Need a fixed size serializer for the track ID. libmkv provides a 64 bit
  28 // one, but not a 32 bit one.
  29 static void Ebml_SerializeUnsigned32(EbmlGlobal* ebml,
  30                                      unsigned long class_id,
  31                                      uint64_t value) {
  32   uint8 size_serialized = 4 | 0x80;
  33   Ebml_WriteID(ebml, class_id);
  34   Ebml_Serialize(ebml, &size_serialized, sizeof(size_serialized), 1);
  35   Ebml_Serialize(ebml, &value, sizeof(value), 4);
  36 }
  37
  38 // Wrapper functor for vpx_codec_destroy().
  39 struct VpxCodecDeleter {
  40   void operator()(vpx_codec_ctx_t* codec) {
  41     vpx_codec_destroy(codec);
  42   }
  43 };
  44
  45 // Wrapper functor for vpx_img_free().
  46 struct VpxImgDeleter {
  47   void operator()(vpx_image_t* image) {
  48     vpx_img_free(image);
  49   }
  50 };
  51
  52 namespace media {
  53
  54 namespace chromeos {
  55
  56 WebmEncoder::WebmEncoder(const base::FilePath& output_path,
  57                          int bitrate,
  58                          bool realtime)
  59     : bitrate_(bitrate),
  60       deadline_(realtime ? VPX_DL_REALTIME : VPX_DL_GOOD_QUALITY),
  61       output_path_(output_path),
  62       has_errors_(false) {
  63   ebml_writer_.write_cb = base::Bind(
  64       &WebmEncoder::EbmlWrite, base::Unretained(this));
  65   ebml_writer_.serialize_cb = base::Bind(
  66       &WebmEncoder::EbmlSerialize, base::Unretained(this));
  67 }
  68
  69 WebmEncoder::~WebmEncoder() {
  70 }
  71
  72 bool WebmEncoder::EncodeFromSprite(const SkBitmap& sprite,
  73                                    int fps_n,
  74                                    int fps_d) {
  75   DCHECK(!sprite.isNull());
  76   DCHECK(!sprite.empty());
  77
  78   has_errors_ = false;
  79   width_ = sprite.width();
  80   height_ = sprite.width();
  81   fps_.num = fps_n;
  82   fps_.den = fps_d;
  83
  84   // Sprite is tiled vertically.
  85   frame_count_ = sprite.height() / width_;
  86
  87   vpx_image_t image;
  88   vpx_img_alloc(&image, VPX_IMG_FMT_I420, width_, height_, 16);
  89   // Ensure that image is freed after return.
  90   scoped_ptr<vpx_image_t, VpxImgDeleter> image_ptr(&image);
  91
  92   const vpx_codec_iface_t* codec_iface = vpx_codec_vp8_cx();
  93   DCHECK(codec_iface);
  94   vpx_codec_err_t ret = vpx_codec_enc_config_default(codec_iface, &config_, 0);
  95   DCHECK_EQ(VPX_CODEC_OK, ret);
  96
  97   config_.rc_target_bitrate = bitrate_;
  98   config_.g_w = width_;
  99   config_.g_h = height_;
 100   config_.g_pass = VPX_RC_ONE_PASS;
 101   config_.g_profile = 0;          // Default profile.
 102   config_.g_threads = kNumEncoderThreads;
 103   config_.rc_min_quantizer = 0;
 104   config_.rc_max_quantizer = 63;  // Maximum possible range.
 105   config_.g_timebase.num = fps_.den;
 106   config_.g_timebase.den = fps_.num;
 107   config_.kf_mode = VPX_KF_AUTO;  // Auto key frames.
 108
 109   vpx_codec_ctx_t codec;
 110   ret = vpx_codec_enc_init(&codec, codec_iface, &config_, 0);
 111   if (ret != VPX_CODEC_OK)
 112     return false;
 113   // Ensure that codec context is freed after return.
 114   scoped_ptr<vpx_codec_ctx_t, VpxCodecDeleter> codec_ptr(&codec);
 115
 116   SkAutoLockPixels lock_sprite(sprite);
 117
 118   const uint8* src = reinterpret_cast<const uint8*>(sprite.getAddr32(0, 0));
 119   size_t src_frame_size = sprite.getSize();
 120   int crop_y = 0;
 121
 122   if (!WriteWebmHeader())
 123     return false;
 124
 125   for (size_t frame = 0; frame < frame_count_ && !has_errors_; ++frame) {
 126     int res = libyuv::ConvertToI420(
 127         src, src_frame_size,
 128         image.planes[VPX_PLANE_Y], image.stride[VPX_PLANE_Y],
 129         image.planes[VPX_PLANE_U], image.stride[VPX_PLANE_U],
 130         image.planes[VPX_PLANE_V], image.stride[VPX_PLANE_V],
 131         0, crop_y,                // src origin
 132         width_, sprite.height(),  // src size
 133         width_, height_,          // dest size
 134         libyuv::kRotate0,
 135         libyuv::FOURCC_ARGB);
 136     if (res) {
 137       has_errors_ = true;
 138       break;
 139     }
 140     crop_y += height_;
 141
 142     ret = vpx_codec_encode(&codec, &image, frame, 1, 0, deadline_);
 143     if (ret != VPX_CODEC_OK) {
 144       has_errors_ = true;
 145       break;
 146     }
 147
 148     vpx_codec_iter_t iter = NULL;
 149     const vpx_codec_cx_pkt_t* packet;
 150     while (!has_errors_ && (packet = vpx_codec_get_cx_data(&codec, &iter))) {
 151       if (packet->kind == VPX_CODEC_CX_FRAME_PKT)
 152         WriteWebmBlock(packet);
 153     }
 154   }
 155
 156   return WriteWebmFooter();
 157 }
 158
 159 bool WebmEncoder::WriteWebmHeader() {
 160   output_ = file_util::OpenFile(output_path_, "wb");
 161   if (!output_)
 162     return false;
 163
 164   // Global header.
 165   StartSubElement(EBML);
 166   {
 167     Ebml_SerializeUnsigned(&ebml_writer_, EBMLVersion, 1);
 168     Ebml_SerializeUnsigned(&ebml_writer_, EBMLReadVersion, 1);
 169     Ebml_SerializeUnsigned(&ebml_writer_, EBMLMaxIDLength, 4);
 170     Ebml_SerializeUnsigned(&ebml_writer_, EBMLMaxSizeLength, 8);
 171     Ebml_SerializeString(&ebml_writer_, DocType, "webm");
 172     Ebml_SerializeUnsigned(&ebml_writer_, DocTypeVersion, 2);
 173     Ebml_SerializeUnsigned(&ebml_writer_, DocTypeReadVersion, 2);
 174   }
 175   EndSubElement();  // EBML
 176
 177   // Single segment with a video track.
 178   StartSubElement(Segment);
 179   {
 180     StartSubElement(Info);
 181     {
 182       // All timecodes in the segment will be expressed in milliseconds.
 183       Ebml_SerializeUnsigned(&ebml_writer_, TimecodeScale, 1000000);
 184       double duration = 1000. * frame_count_ * fps_.den / fps_.num;
 185       Ebml_SerializeFloat(&ebml_writer_, Segment_Duration, duration);
 186     }
 187     EndSubElement();  // Info
 188
 189     StartSubElement(Tracks);
 190     {
 191       StartSubElement(TrackEntry);
 192       {
 193         Ebml_SerializeUnsigned(&ebml_writer_, TrackNumber, 1);
 194         Ebml_SerializeUnsigned32(&ebml_writer_, TrackUID, 1);
 195         Ebml_SerializeUnsigned(&ebml_writer_, TrackType, 1);  // Video
 196         Ebml_SerializeString(&ebml_writer_, CodecID, "V_VP8");
 197
 198         StartSubElement(Video);
 199         {
 200           Ebml_SerializeUnsigned(&ebml_writer_, PixelWidth, width_);
 201           Ebml_SerializeUnsigned(&ebml_writer_, PixelHeight, height_);
 202           Ebml_SerializeUnsigned(&ebml_writer_, StereoMode, 0);  // Mono
 203           float fps = static_cast<float>(fps_.num) / fps_.den;
 204           Ebml_SerializeFloat(&ebml_writer_, FrameRate, fps);
 205         }
 206         EndSubElement();  // Video
 207       }
 208       EndSubElement();  // TrackEntry
 209     }
 210     EndSubElement();  // Tracks
 211
 212     StartSubElement(Cluster); {
 213       Ebml_SerializeUnsigned(&ebml_writer_, Timecode, 0);
 214     }  // Cluster left open.
 215   }  // Segment left open.
 216
 217   // No check for |has_errors_| here because |false| is only returned when
 218   // opening file fails.
 219   return true;
 220 }
 221
 222 void WebmEncoder::WriteWebmBlock(const vpx_codec_cx_pkt_t* packet) {
 223   bool is_keyframe = packet->data.frame.flags & VPX_FRAME_IS_KEY;
 224   int64_t pts_ms = 1000 * packet->data.frame.pts * fps_.den / fps_.num;
 225
 226   DVLOG(1) << "Video packet @" << pts_ms << " ms "
 227            << packet->data.frame.sz << " bytes "
 228            << (is_keyframe ? "K" : "");
 229
 230   Ebml_WriteID(&ebml_writer_, SimpleBlock);
 231
 232   uint32 block_length = (packet->data.frame.sz + 4) | 0x10000000;
 233   EbmlSerializeHelper(&block_length, 4);
 234
 235   uint8 track_number = 1 | 0x80;
 236   EbmlSerializeHelper(&track_number, 1);
 237
 238   EbmlSerializeHelper(&pts_ms, 2);
 239
 240   uint8 flags = 0;
 241   if (is_keyframe)
 242     flags |= 0x80;
 243   if (packet->data.frame.flags & VPX_FRAME_IS_INVISIBLE)
 244     flags |= 0x08;
 245   EbmlSerializeHelper(&flags, 1);
 246
 247   EbmlWrite(packet->data.frame.buf, packet->data.frame.sz);
 248 }
 249
 250 bool WebmEncoder::WriteWebmFooter() {
 251   EndSubElement();  // Cluster
 252   EndSubElement();  // Segment
 253   DCHECK(ebml_sub_elements_.empty());
 254   return file_util::CloseFile(output_) && !has_errors_;
 255 }
 256
 257 void WebmEncoder::StartSubElement(unsigned long class_id) {
 258   Ebml_WriteID(&ebml_writer_, class_id);
 259   ebml_sub_elements_.push(ftell(output_));
 260   static const uint64_t kUnknownLen = 0x01FFFFFFFFFFFFFFLLU;
 261   EbmlSerializeHelper(&kUnknownLen, 8);
 262 }
 263
 264 void WebmEncoder::EndSubElement() {
 265   DCHECK(!ebml_sub_elements_.empty());
 266
 267   long int end_pos = ftell(output_);
 268   long int start_pos = ebml_sub_elements_.top();
 269   ebml_sub_elements_.pop();
 270
 271   uint64_t size = (end_pos - start_pos - 8) | 0x0100000000000000ULL;
 272   // Seek to the beginning of the sub-element and patch in the calculated size.
 273   if (fseek(output_, start_pos, SEEK_SET)) {
 274     has_errors_ = true;
 275     LOG(ERROR) << "Error writing to " << output_path_.value();
 276   }
 277   EbmlSerializeHelper(&size, 8);
 278
 279   // Restore write position.
 280   if (fseek(output_, end_pos, SEEK_SET)) {
 281     has_errors_ = true;
 282     LOG(ERROR) << "Error writing to " << output_path_.value();
 283   }
 284 }
 285
 286 void WebmEncoder::EbmlWrite(const void* buffer,
 287                             unsigned long len) {
 288   if (fwrite(buffer, 1, len, output_) != len) {
 289     has_errors_ = true;
 290     LOG(ERROR) << "Error writing to " << output_path_.value();
 291   }
 292 }
 293
 294 template <class T>
 295 void WebmEncoder::EbmlSerializeHelper(const T* buffer, unsigned long len) {
 296   for (int i = len - 1; i >= 0; i--) {
 297     uint8 c = *buffer >> (i * CHAR_BIT);
 298     EbmlWrite(&c, 1);
 299   }
 300 }
 301
 302 void WebmEncoder::EbmlSerialize(const void* buffer,
 303                                 int buffer_size,
 304                                 unsigned long len) {
 305   switch (buffer_size) {
 306     case 1:
 307       return EbmlSerializeHelper(static_cast<const int8_t*>(buffer), len);
 308     case 2:
 309       return EbmlSerializeHelper(static_cast<const int16_t*>(buffer), len);
 310     case 4:
 311       return EbmlSerializeHelper(static_cast<const int32_t*>(buffer), len);
 312     case 8:
 313       return EbmlSerializeHelper(static_cast<const int64_t*>(buffer), len);
 314     default:
 315       NOTREACHED() << "Invalid EbmlSerialize length: " << len;
 316   }
 317 }
 318
 319 }  // namespace chromeos
 320
 321 }  // namespace media