Define default

Author: NicolasHug

src/torchcodec/_core/Encoder.cpp

@@ -50,12 +50,11 @@ AudioEncoder::AudioEncoder(
   TORCH_CHECK(avCodecContext != nullptr, "Couldn't allocate codec context.");
   avCodecContext_.reset(avCodecContext);
 
-  // TODO-ENCODING I think 0 sets the bit rate to the minimum supported.
-  // That's not what the ffmpeg CLI would choose by default, so we should try to
-  // do the same.
   if (bit_rate.has_value()) {
     TORCH_CHECK(*bit_rate >= 0, "bit_rate=", *bit_rate, " must be >= 0.");
   }
+  // bit_rate=None defaults to 0, which is what the FFmpeg CLI seems to use as
+  // well when "-b:a" isn't specified.
   avCodecContext_->bit_rate = bit_rate.value_or(0);
 
   avCodecContext_->sample_rate = sampleRate_;

test/test_ops.py

@@ -1142,7 +1142,7 @@ def test_round_trip(self, tmp_path):
 
     # TODO-ENCODING: test more encoding formats
     @pytest.mark.parametrize("asset", (NASA_AUDIO_MP3, SINE_MONO_S32))
-    @pytest.mark.parametrize("bit_rate", (None, 0, 1, 44_100))
+    @pytest.mark.parametrize("bit_rate", (None, 0, 44_100, 999_999_999))
     def test_against_cli(self, asset, bit_rate, tmp_path):
         # Encodes samples with our encoder and with the FFmpeg CLI, and checks
         # that both decoded outputs are equal
@@ -1151,12 +1151,9 @@ def test_against_cli(self, asset, bit_rate, tmp_path):
         encoded_by_us = tmp_path / "our_output.mp3"
 
         subprocess.run(
-            [
-                "ffmpeg",
-                "-i",
-                str(asset.path),
-                "-b:a",
-                f"{bit_rate or 0}",  # None == 0 (for now!)
+            ["ffmpeg", "-i", str(asset.path)]
+            + (["-b:a", f"{bit_rate}"] if bit_rate is not None else [])
+            + [
                 str(encoded_by_ffmpeg),
             ],
             capture_output=True,