Add config change support to FFmpegVideoDecoder

media/filters/ffmpeg_video_decoder.cc

Index: media/filters/ffmpeg_video_decoder.cc
diff --git a/media/filters/ffmpeg_video_decoder.cc b/media/filters/ffmpeg_video_decoder.cc
index 7fc80885d474546d33ad5a0676906a02b2d546df..6bcbdabc8b8b5911b12f1e2b192affabb494dee5 100644
--- a/media/filters/ffmpeg_video_decoder.cc
+++ b/media/filters/ffmpeg_video_decoder.cc
@@ -83,6 +83,8 @@ int FFmpegVideoDecoder::GetVideoBuffer(AVCodecContext* codec_context,
 
   scoped_refptr<VideoFrame> video_frame =
       VideoFrame::CreateFrame(format, width, height,
+                              natural_size_.width(),
+                              natural_size_.height(),
                               kNoTimestamp(), kNoTimestamp());
 
   for (int i = 0; i < 3; i++) {
@@ -158,34 +160,13 @@ void FFmpegVideoDecoder::Initialize(const scoped_refptr<DemuxerStream>& stream,
     return;
   }
 
-  // Initialize AVCodecContext structure.
-  codec_context_ = avcodec_alloc_context3(NULL);
-  VideoDecoderConfigToAVCodecContext(config, codec_context_);
-
-  // Enable motion vector search (potentially slow), strong deblocking filter
-  // for damaged macroblocks, and set our error detection sensitivity.
-  codec_context_->error_concealment = FF_EC_GUESS_MVS | FF_EC_DEBLOCK;
-  codec_context_->err_recognition = AV_EF_CAREFUL;
-  codec_context_->thread_count = GetThreadCount(codec_context_->codec_id);
-  codec_context_->opaque = this;
-  codec_context_->flags |= CODEC_FLAG_EMU_EDGE;
-  codec_context_->get_buffer = GetVideoBufferImpl;
-  codec_context_->release_buffer = ReleaseVideoBufferImpl;
-
-  AVCodec* codec = avcodec_find_decoder(codec_context_->codec_id);
-  if (!codec) {
-    status_cb.Run(PIPELINE_ERROR_DECODE);
-    return;
-  }
-
-  if (avcodec_open2(codec_context_, codec, NULL) < 0) {
+  if (!AllocateFFmpegResources(config)) {

[Ami GONE FROM CHROMIUM, 2012/07/13 00:59:05]

I wonder if it doesn't make sense to inline AFFMR() into HandleConfigChange and
call the latter from here (and make it tolerant to not having a "previous" set
of ffmpeg resources to release).

     status_cb.Run(PIPELINE_ERROR_DECODE);
     return;
   }
 
   // Success!
   state_ = kNormal;
-  av_frame_ = avcodec_alloc_frame();
   natural_size_ = config.natural_size();
   frame_rate_numerator_ = config.frame_rate_numerator();
   frame_rate_denominator_ = config.frame_rate_denominator();

[Ami GONE FROM CHROMIUM, 2012/07/13 00:59:05]

...in which case these can go away

@@ -301,10 +282,18 @@ void FFmpegVideoDecoder::DoDecodeBuffer(
     return;
   }
 
-  if (status != DemuxerStream::kOk) {
-    DecoderStatus decoder_status =
-        (status == DemuxerStream::kAborted) ? kOk : kDecodeError;
-    base::ResetAndReturn(&read_cb_).Run(decoder_status, NULL);
+  if (status == DemuxerStream::kAborted) {
+    base::ResetAndReturn(&read_cb_).Run(kOk, NULL);
+    return;
+  }
+
+  if (status == DemuxerStream::kConfigChanged) {
+    if (!HandleConfigChange()) {
+      base::ResetAndReturn(&read_cb_).Run(kDecodeError, NULL);
+      return;
+    }
+
+    ReadFromDemuxerStream();
     return;
   }
 
@@ -477,6 +466,36 @@ void FFmpegVideoDecoder::DeliverFrame(
   base::ResetAndReturn(&read_cb_).Run(kOk, video_frame);
 }
 
+bool FFmpegVideoDecoder::AllocateFFmpegResources(
+    const VideoDecoderConfig& config) {
+  DCHECK(!codec_context_);
+  DCHECK(!av_frame_);
+
+  // Initialize AVCodecContext structure.
+  codec_context_ = avcodec_alloc_context3(NULL);
+  VideoDecoderConfigToAVCodecContext(config, codec_context_);
+
+  // Enable motion vector search (potentially slow), strong deblocking filter
+  // for damaged macroblocks, and set our error detection sensitivity.
+  codec_context_->error_concealment = FF_EC_GUESS_MVS | FF_EC_DEBLOCK;
+  codec_context_->err_recognition = AV_EF_CAREFUL;
+  codec_context_->thread_count = GetThreadCount(codec_context_->codec_id);
+  codec_context_->opaque = this;
+  codec_context_->flags |= CODEC_FLAG_EMU_EDGE;
+  codec_context_->get_buffer = GetVideoBufferImpl;
+  codec_context_->release_buffer = ReleaseVideoBufferImpl;
+
+  AVCodec* codec = avcodec_find_decoder(codec_context_->codec_id);
+  if (!codec)
+    return false;
+
+  if (avcodec_open2(codec_context_, codec, NULL) < 0)
+    return false;
+
+  av_frame_ = avcodec_alloc_frame();
+  return true;
+}
+
 void FFmpegVideoDecoder::ReleaseFFmpegResources() {
   if (codec_context_) {
     av_free(codec_context_->extradata);
@@ -490,4 +509,20 @@ void FFmpegVideoDecoder::ReleaseFFmpegResources() {
   }
 }
 
+bool FFmpegVideoDecoder::HandleConfigChange() {
+  const VideoDecoderConfig& config = demuxer_stream_->video_decoder_config();
+
+  if (!config.IsValidConfig())
+    return false;
+
+  ReleaseFFmpegResources();
+  if (!AllocateFFmpegResources(config))
+    return false;
+
+  natural_size_ = config.natural_size();
+  frame_rate_numerator_ = config.frame_rate_numerator();
+  frame_rate_denominator_ = config.frame_rate_denominator();
+  return true;
+}
+
 }  // namespace media