media/base/media_file_checker.cc

   1 // Copyright 2013 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/base/media_file_checker.h"
   6
   7 #include <map>
   8
   9 #include "base/bind.h"
  10 #include "base/time/time.h"
  11 #include "media/ffmpeg/ffmpeg_common.h"
  12 #include "media/filters/blocking_url_protocol.h"
  13 #include "media/filters/ffmpeg_glue.h"
  14 #include "media/filters/file_data_source.h"
  15
  16 namespace media {
  17
  18 static const int64 kMaxCheckTimeInSeconds = 5;
  19
  20 static void OnError(bool* called) {
  21   *called = false;
  22 }
  23
  24 MediaFileChecker::MediaFileChecker(base::File file) : file_(file.Pass()) {
  25 }
  26
  27 MediaFileChecker::~MediaFileChecker() {
  28 }
  29
  30 bool MediaFileChecker::Start(base::TimeDelta check_time) {
  31   media::FileDataSource source(file_.Pass());
  32   bool read_ok = true;
  33   media::BlockingUrlProtocol protocol(&source, base::Bind(&OnError, &read_ok));
  34   media::FFmpegGlue glue(&protocol);
  35   AVFormatContext* format_context = glue.format_context();
  36
  37   if (!glue.OpenContext())
  38     return false;
  39
  40   if (avformat_find_stream_info(format_context, NULL) < 0)
  41     return false;
  42
  43   // Remember the codec context for any decodable audio or video streams.
  44   std::map<int, AVCodecContext*> stream_contexts;
  45   for (size_t i = 0; i < format_context->nb_streams; ++i) {
  46     AVCodecContext* c = format_context->streams[i]->codec;
  47     if (c->codec_type == AVMEDIA_TYPE_AUDIO ||
  48         c->codec_type == AVMEDIA_TYPE_VIDEO) {
  49       AVCodec* codec = avcodec_find_decoder(c->codec_id);
  50       if (codec && avcodec_open2(c, codec, NULL) >= 0)
  51         stream_contexts[i] = c;
  52     }
  53   }
  54
  55   if (stream_contexts.size() == 0)
  56     return false;
  57
  58   AVPacket packet;
  59   scoped_ptr<AVFrame, media::ScopedPtrAVFreeFrame> frame(av_frame_alloc());
  60   int result = 0;
  61
  62   const base::TimeTicks deadline = base::TimeTicks::Now() +
  63       std::min(check_time,
  64                base::TimeDelta::FromSeconds(kMaxCheckTimeInSeconds));
  65   do {
  66     result = av_read_frame(glue.format_context(), &packet);
  67     if (result < 0)
  68       break;
  69     result = av_dup_packet(&packet);
  70     if (result < 0)
  71       break;
  72
  73     std::map<int, AVCodecContext*>::const_iterator it =
  74         stream_contexts.find(packet.stream_index);
  75     if (it == stream_contexts.end()) {
  76       av_free_packet(&packet);
  77       continue;
  78     }
  79     AVCodecContext* av_context = it->second;
  80
  81     int frame_decoded = 0;
  82     if (av_context->codec_type == AVMEDIA_TYPE_AUDIO) {
  83       // A shallow copy of packet so we can slide packet.data as frames are
  84       // decoded; otherwise av_free_packet() will corrupt memory.
  85       AVPacket temp_packet = packet;
  86       do {
  87         result = avcodec_decode_audio4(av_context, frame.get(), &frame_decoded,
  88                                        &temp_packet);
  89         if (result < 0)
  90           break;
  91         av_frame_unref(frame.get());
  92         temp_packet.size -= result;
  93         temp_packet.data += result;
  94         frame_decoded = 0;
  95       } while (temp_packet.size > 0);
  96     } else if (av_context->codec_type == AVMEDIA_TYPE_VIDEO) {
  97       result = avcodec_decode_video2(av_context, frame.get(), &frame_decoded,
  98                                      &packet);
  99       if (result >= 0 && frame_decoded)
 100         av_frame_unref(frame.get());
 101     }
 102     av_free_packet(&packet);
 103   } while (base::TimeTicks::Now() < deadline && read_ok && result >= 0);
 104
 105   return read_ok && (result == AVERROR_EOF || result >= 0);
 106 }
 107
 108 }  // namespace media