incorporate suggestions

Author: Daniel Flores

src/torchcodec/_core/FFMPEGCommon.cpp

@@ -67,7 +67,7 @@ int getNumChannels(const UniqueAVFrame& avFrame) {
   // to allow successful initialization of SwrContext
   if (numChannels == 0 && avFrame->channels > 0) {
     avFrame->channel_layout = av_get_default_channel_layout(avFrame->channels);
-    return avFrame->channels;
+    numChannels = avFrame->channels;
   }
   return numChannels;
 #endif

test/test_decoders.py

@@ -1692,14 +1692,14 @@ def test_decode_s16_ffmpeg4(self):
         assert decoder.metadata.sample_rate == asset.sample_rate
         assert decoder.metadata.sample_format == asset.sample_format
 
-        test_frames = decoder.get_samples_played_in_range()
-        assert test_frames.data.shape[0] == decoder.metadata.num_channels
-        assert test_frames.sample_rate == decoder.metadata.sample_rate
+        test_samples = decoder.get_samples_played_in_range()
+        assert test_samples.data.shape[0] == decoder.metadata.num_channels
+        assert test_samples.sample_rate == decoder.metadata.sample_rate
         reference_frames = asset.get_frame_data_by_range(
             start=0, stop=1, stream_index=0
         )
         torch.testing.assert_close(
-            test_frames.data[0], reference_frames, atol=0, rtol=0
+            test_samples.data[0], reference_frames, atol=0, rtol=0
         )
 
     @pytest.mark.parametrize("asset", (NASA_AUDIO, NASA_AUDIO_MP3))