Resolve some compilation warnings (#3471)

Summary:
- FFmpeg 6 deprecated attributes
- Guard CUDA specific functions not used in CPU builds

Pull Request resolved: https://github.com/pytorch/audio/pull/3471

Differential Revision: D47402174

Pulled By: mthrok

fbshipit-source-id: 00c0719ab1849b50c0b56b03d8fb38bc7aa74538

torchaudio/csrc/ffmpeg/filter_graph.cpp

@@ -186,7 +186,8 @@ FilterGraphOutputInfo FilterGraph::get_output_info() const {
   switch (l->type) {
     case AVMEDIA_TYPE_AUDIO: {
       ret.sample_rate = l->sample_rate;
-#if LIBAVFILTER_VERSION_MAJOR >= 8 && LIBAVFILTER_VERSION_MINOR >= 44
+#if LIBAVFILTER_VERSION_MAJOR >= 9 || \
+    (LIBAVFILTER_VERSION_MAJOR == 8 && LIBAVFILTER_VERSION_MINOR >= 44)
       ret.num_channels = l->ch_layout.nb_channels;
 #else
       // Before FFmpeg 5.1

torchaudio/csrc/ffmpeg/stream_reader/conversion.cpp

@@ -98,6 +98,7 @@ torch::Tensor get_image_buffer(
       shape, torch::TensorOptions().dtype(dtype).layout(torch::kStrided));
 }
 
+#ifdef USE_CUDA
 torch::Tensor get_image_buffer(
     at::IntArrayRef shape,
     torch::Device device,
@@ -109,6 +110,7 @@ torch::Tensor get_image_buffer(
           .layout(torch::kStrided)
           .device(device));
 }
+#endif
 
 } // namespace
 

torchaudio/csrc/ffmpeg/stream_reader/stream_processor.cpp

@@ -27,6 +27,7 @@ AVCodecContextPtr alloc_codec_context(
   return AVCodecContextPtr(codec_ctx);
 }
 
+#ifdef USE_CUDA
 const AVCodecHWConfig* get_cuda_config(const AVCodec* codec) {
   for (int i = 0;; ++i) {
     const AVCodecHWConfig* config = avcodec_get_hw_config(codec, i);
@@ -80,6 +81,7 @@ enum AVPixelFormat get_hw_format(
   TORCH_WARN("Failed to get HW surface format.");
   return AV_PIX_FMT_NONE;
 }
+#endif
 
 AVBufferRef* get_hw_frames_ctx(AVCodecContext* codec_ctx) {
   AVBufferRef* p = av_hwframe_ctx_alloc(codec_ctx->hw_device_ctx);
@@ -138,10 +140,12 @@ void open_codec(
     av_dict_set(&opts, "threads", "1", 0);
   }
 
+#if LIBAVUTIL_VERSION_MAJOR < 58
   if (!codec_ctx->channel_layout) {
     codec_ctx->channel_layout =
         av_get_default_channel_layout(codec_ctx->channels);
   }
+#endif
 
   int ret = avcodec_open2(codec_ctx, codec_ctx->codec, &opts);
   clean_up_dict(opts);
@@ -332,7 +336,12 @@ int StreamProcessor::process_packet(AVPacket* packet) {
         // This is because they might be intra-frames not in chronological
         // order. In this case, we use received frames as-is in the order they
         // are received.
+
+#if LIBAVCODEC_VERSION_MAJOR >= 60
+        frame->pts = codec_ctx->frame_num + 1;
+#else
         frame->pts = codec_ctx->frame_number + 1;
+#endif
       } else {
         frame->pts = frame->best_effort_timestamp;
       }

torchaudio/csrc/ffmpeg/stream_writer/encode_process.cpp

@@ -527,6 +527,7 @@ void configure_video_codec_ctx(
   }
 }
 
+#ifdef USE_CUDA
 void configure_hw_accel(AVCodecContext* ctx, const std::string& hw_accel) {
   torch::Device device{hw_accel};
   TORCH_CHECK(
@@ -570,6 +571,7 @@ void configure_hw_accel(AVCodecContext* ctx, const std::string& hw_accel) {
       "Failed to initialize CUDA frame context: ",
       av_err2string(ret));
 }
+#endif
 
 ////////////////////////////////////////////////////////////////////////////////
 // AVStream