Bug 1364870: [ffmpeg] only check format if frame has been decoded. r=gerald

The format member isn't set when an audio frame hasn't been decoded yet.

MozReview-Commit-ID: IgUj6bjVzdF

--HG--
extra : rebase_source : bb47fa523384f9a85ee7d0ed5b6de4fe2c73526a

dom/media/platforms/ffmpeg/FFmpegAudioDecoder.cpp

@@ -153,6 +153,7 @@ FFmpegAudioDecoder<LIBAV_VER>::ProcessDecode(MediaRawData* aSample)
         __func__);
     }
 
+    if (decoded) {
       if (mFrame->format != AV_SAMPLE_FMT_FLT &&
           mFrame->format != AV_SAMPLE_FMT_FLTP &&
           mFrame->format != AV_SAMPLE_FMT_S16 &&
@@ -162,11 +163,10 @@ FFmpegAudioDecoder<LIBAV_VER>::ProcessDecode(MediaRawData* aSample)
         return DecodePromise::CreateAndReject(
           MediaResult(
             NS_ERROR_DOM_MEDIA_DECODE_ERR,
-          RESULT_DETAIL("FFmpeg audio decoder outputs unsupported audio format")),
+            RESULT_DETAIL(
+              "FFmpeg audio decoder outputs unsupported audio format")),
           __func__);
       }
-
-    if (decoded) {
       uint32_t numChannels = mCodecContext->channels;
       AudioConfig::ChannelLayout layout(numChannels);
       if (!layout.IsValid()) {