This tool demonstrates the use of the Media Foundation H.264 decoder as a sta...

media/mf/file_reader_util.cc

+// Copyright (c) 2010 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.
+//
+// Borrowed from media/tools/omx_test/file_reader_util.cc.
+// Added some functionalities related to timestamps on packets.
+
+#include "media/mf/file_reader_util.h"
+
+#include <algorithm>
+
+#include "base/scoped_comptr_win.h"
+#include "base/logging.h"
+#include "media/ffmpeg/ffmpeg_common.h"
+#include "media/filters/bitstream_converter.h"
+
+namespace media {
+
+//////////////////////////////////////////////////////////////////////////////
+// FFmpegFileReader
+FFmpegFileReader::FFmpegFileReader(const std::string& filename)
+    : filename_(filename),
+      format_context_(NULL),
+      codec_context_(NULL),
+      target_stream_(-1),
+      converter_(NULL),
+      end_of_stream_(false) {
+}
+
+FFmpegFileReader::~FFmpegFileReader() {
+  if (format_context_)
+    av_close_input_file(format_context_);
+}
+
+bool FFmpegFileReader::Initialize() {
+  int result = av_open_input_file(&format_context_, filename_.c_str(),
+                                  NULL, 0, NULL);
+  if (result < 0) {
+    switch (result) {
+      case AVERROR_NOFMT:
+        LOG(ERROR) << "Error: File format not supported "
+                  << filename_;
+        break;
+      default:
+        LOG(ERROR) << "Error: Could not open input for "
+                   << filename_ << ": " << result;
+        break;
+    }
+    return false;
+  }
+  if (av_find_stream_info(format_context_) < 0) {
+    LOG(ERROR) << "can't use FFmpeg to parse stream info";
+    return false;
+  }
+
+  for (size_t i = 0; i < format_context_->nb_streams; ++i) {
+    codec_context_ = format_context_->streams[i]->codec;
+
+    // Find the video stream.
+    if (codec_context_->codec_type == CODEC_TYPE_VIDEO) {
+      target_stream_ = i;
+      break;
+    }
+  }
+  if (target_stream_ == -1) {
+    LOG(ERROR) << "no video in the stream";
+    return false;
+  }
+
+  // Initialize the bitstream filter if needed.
+  // TODO(hclam): find a better way to identify mp4 container.
+  if (codec_context_->codec_id == CODEC_ID_H264) {
+    converter_.reset(new media::FFmpegBitstreamConverter(
+        "h264_mp4toannexb", codec_context_));
+  } else if (codec_context_->codec_id == CODEC_ID_MPEG4) {
+    converter_.reset(new media::FFmpegBitstreamConverter(
+        "mpeg4video_es", codec_context_));
+  } else if (codec_context_->codec_id == CODEC_ID_WMV3) {
+    converter_.reset(new media::FFmpegBitstreamConverter(
+        "vc1_asftorcv", codec_context_));
+  } else if (codec_context_->codec_id == CODEC_ID_VC1) {
+    converter_.reset(new media::FFmpegBitstreamConverter(
+        "vc1_asftoannexg", codec_context_));
+  }
+  if (converter_.get() && !converter_->Initialize()) {
+    converter_.reset();
+    LOG(ERROR) << "failed to initialize h264_mp4toannexb filter";
+    return false;
+  }
+  return true;
+}
+
+void FFmpegFileReader::Read(uint8** output, int* size) {
+  Read(output, size, NULL, NULL);
+}
+
+void FFmpegFileReader::Read(uint8** output, int* size, int64* timestamp,
+                            int64* duration) {
+  if (!format_context_ || !codec_context_ || target_stream_ == -1) {
+    *size = 0;
+    *output = NULL;
+    return;
+  }
+  AVPacket packet;
+  bool found = false;
+  while (!found) {
+    int result = av_read_frame(format_context_, &packet);
+    if (result < 0) {
+      *output = NULL;
+      *size = 0;
+      end_of_stream_ = true;
+      return;
+    }
+    if (packet.stream_index == target_stream_) {
+      if (converter_.get() && !converter_->ConvertPacket(&packet)) {
+        LOG(ERROR) << "failed to convert AVPacket";
+      }
+      *output = new uint8[packet.size];
+      if (*output == NULL) {
+        LOG(ERROR) << "Failed to allocate buffer for annex b stream";
+        *size = 0;
+        return;
+      }
+      *size = packet.size;
+      memcpy(*output, packet.data, packet.size);
+      if (duration) {
+        if (packet.duration == 0) {
+          LOG(WARNING) << "Packet duration not known";
+        }
+        // This is in AVCodecContext::time_base units
+        *duration = ConvertFFmpegTimeBaseTo100Ns(packet.duration);
+      }
+      if (timestamp) {
+        if (packet.pts == AV_NOPTS_VALUE) {
+          LOG(ERROR) << "Packet presentation time not known";
+          *timestamp = 0L;
+        } else {
+          // This is in AVCodecContext::time_base units
+          *timestamp = ConvertFFmpegTimeBaseTo100Ns(packet.pts);
+        }
+      }
+      found = true;
+    }
+    av_free_packet(&packet);
+  }
+}
+
+bool FFmpegFileReader::GetFrameRate(int* num, int *denom) const {
+  if (!codec_context_)
+    return false;
+
+  // time_base = 1 / frame_rate
+  *denom = codec_context_->time_base.num;
+  *num = codec_context_->time_base.den;
+  if (denom == 0) {
+    *num = 0;
+    return false;
+  }
+  return true;
+}
+
+bool FFmpegFileReader::GetWidth(int* width) const {
+  if (!codec_context_)
+    return false;
+  *width = codec_context_->width;
+  return true;
+}
+
+bool FFmpegFileReader::GetHeight(int* height) const {
+  if (!codec_context_)
+    return false;
+  *height = codec_context_->height;
+  return true;
+}
+
+bool FFmpegFileReader::GetAspectRatio(int* num, int* denom) const {
+  if (!codec_context_)
+    return false;
+  AVRational aspect_ratio = codec_context_->sample_aspect_ratio;
+  if (aspect_ratio.num == 0 || aspect_ratio.den == 0)
+    return false;
+  *num = aspect_ratio.num;
+  *denom = aspect_ratio.den;
+  return true;
+}
+
+int64 FFmpegFileReader::ConvertFFmpegTimeBaseTo100Ns(
+    int64 time_base_unit) const {
+  // FFmpeg units after time base conversion seems to be actually given in
+  // milliseconds (instead of seconds...) so we need to multiply it by a factor
+  // of 10,000 to convert it into units compatible with MF.
+  CHECK(codec_context_) << "Codec context needs to be initialized";
+  return time_base_unit * 10000 * codec_context_->time_base.num /
+         codec_context_->time_base.den;
+}
+
+}  // namespace media