Allow ffmpeg to process individual NALU rather than require frames.

The new video-decoding PPAPI accepts NALU's for H264 streams.

BUG=281689
TEST=Example in the pending CL for the new PPAPI

Review URL: https://codereview.chromium.org/301243008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@275601 0039d316-1c4b-4281-b951-d872f2087c98

media/filters/ffmpeg_video_decoder.cc

@@ -68,7 +68,8 @@ static void ReleaseVideoBufferImpl(void* opaque, uint8* data) {
 
 FFmpegVideoDecoder::FFmpegVideoDecoder(
     const scoped_refptr<base::SingleThreadTaskRunner>& task_runner)
-    : task_runner_(task_runner), state_(kUninitialized) {}
+    : task_runner_(task_runner), state_(kUninitialized),
+      decode_nalus_(false) {}
 
 int FFmpegVideoDecoder::GetVideoBuffer(struct AVCodecContext* codec_context,
                                        AVFrame* frame,
@@ -360,6 +361,9 @@ bool FFmpegVideoDecoder::ConfigureDecoder(bool low_delay) {
   codec_context_->get_buffer2 = GetVideoBufferImpl;
   codec_context_->refcounted_frames = 1;
 
+  if (decode_nalus_)
+    codec_context_->flags2 |= CODEC_FLAG2_CHUNKS;
+
   AVCodec* codec = avcodec_find_decoder(codec_context_->codec_id);
   if (!codec || avcodec_open2(codec_context_.get(), codec, NULL) < 0) {
     ReleaseFFmpegResources();

media/filters/ffmpeg_video_decoder.h

@@ -31,6 +31,10 @@ class MEDIA_EXPORT FFmpegVideoDecoder : public VideoDecoder {
       const scoped_refptr<base::SingleThreadTaskRunner>& task_runner);
   virtual ~FFmpegVideoDecoder();
 
+  // Allow decoding of individual NALU. Entire frames are required by default.
+  // Disables low-latency mode. Must be called before Initialize().
+  void set_decode_nalus(bool decode_nalus) { decode_nalus_ = decode_nalus; }
+
   // VideoDecoder implementation.
   virtual void Initialize(const VideoDecoderConfig& config,
                           bool low_delay,
@@ -84,6 +88,8 @@ class MEDIA_EXPORT FFmpegVideoDecoder : public VideoDecoder {
 
   VideoFramePool frame_pool_;
 
+  bool decode_nalus_;
+
   DISALLOW_COPY_AND_ASSIGN(FFmpegVideoDecoder);
 };