remove comments

Author: NicolasHug

src/torchcodec/_core/AudioConverter.cpp

@@ -99,6 +99,9 @@ torch::stable::Tensor AudioConverter::convert(
     src_planes[channel] = base + channel * bytes_per_channel;
   }
 
+  // TODO_API_BREAKDOWN CC P2: the CPUDeviceInterface relies on
+  // swr_convert_to_tensor but only for flushing. We effectively have two
+  // code-paths doing libswresample conversion. Worth aligning.
   return swr_convert_to_tensor(
       swr_context_,
       src_planes.data(),

src/torchcodec/_core/AudioConverter.h

@@ -16,38 +16,20 @@ namespace facebook::torchcodec {
 // Audio conversion building block: turns a decoded frame's samples, in the
 // codec's own sample type, into normalized float32 ones - optionally at another
 // sample rate, and with another channel count.
-//
-// Unlike ColorConverter this is a stream processor, not a function of its
-// input, because resampling is an interpolation filter: the sample it emits at
-// a given instant is a weighted sum of input samples on both sides of it. So
-// swresample holds the tail of each frame back until the next one arrives,
-// which means convert() emits fewer samples than it was given (sometimes none),
-// drain() is needed to get the last ones out, and frames must be fed in order.
-// reset() drops that state, and is what a caller must do after seeking.
-//
+
 // Not thread-safe.
 class FORCE_PUBLIC_VISIBILITY AudioConverter {
  public:
-  // Both default to the source's own value, i.e. to no conversion. Note that
-  // the sample *type* is always converted, to float32.
   explicit AudioConverter(
       std::optional<int> sample_rate = std::nullopt,
       std::optional<int> num_channels = std::nullopt);
 
-  // `samples` is a contiguous [num_channels, num_samples] tensor in the
-  // source's own sample type, i.e. exactly what audio_samples() produces.
-  // Returns the samples that are now computable, as float32
-  // [out_num_channels, N] - and N may well be 0.
   torch::stable::Tensor convert(
       const torch::stable::Tensor& samples,
       int sample_rate);
 
-  // The samples swresample was still holding on to. Callers who skip this lose
-  // the tail of the stream.
   torch::stable::Tensor drain();
 
-  // Drop the resampler's buffered state and start over, so that the next
-  // convert() call reconfigures from the samples it is given.
   void reset();
 
   bool has_converted_samples() const {

src/torchcodec/_core/FFMPEGCommon.cpp

@@ -557,6 +557,7 @@ SwrContext* create_swr_context(
       out_layout);
 }
 
+// TODO Other places use the built-in swr_get_out_samples. We should align.
 int64_t get_swr_output_num_samples_bound(
     const UniqueSwrContext& swr_context,
     int num_src_samples,