Rename FilterState into FilterGraphContext (#478)

Author: NicolasHug

src/torchcodec/decoders/_core/VideoDecoder.cpp

@@ -337,12 +337,12 @@ void VideoDecoder::createFilterGraph(
     StreamInfo& streamInfo,
     int expectedOutputHeight,
     int expectedOutputWidth) {
-  FilterState& filterState = streamInfo.filterState;
-  filterState.filterGraph.reset(avfilter_graph_alloc());
-  TORCH_CHECK(filterState.filterGraph.get() != nullptr);
+  FilterGraphContext& filterGraphContext = streamInfo.filterGraphContext;
+  filterGraphContext.filterGraph.reset(avfilter_graph_alloc());
+  TORCH_CHECK(filterGraphContext.filterGraph.get() != nullptr);
 
   if (streamInfo.videoStreamOptions.ffmpegThreadCount.has_value()) {
-    filterState.filterGraph->nb_threads =
+    filterGraphContext.filterGraph->nb_threads =
         streamInfo.videoStreamOptions.ffmpegThreadCount.value();
   }
 
@@ -360,25 +360,25 @@ void VideoDecoder::createFilterGraph(
              << codecContext->sample_aspect_ratio.den;
 
   int ffmpegStatus = avfilter_graph_create_filter(
-      &filterState.sourceContext,
+      &filterGraphContext.sourceContext,
       buffersrc,
       "in",
       filterArgs.str().c_str(),
       nullptr,
-      filterState.filterGraph.get());
+      filterGraphContext.filterGraph.get());
   if (ffmpegStatus < 0) {
     throw std::runtime_error(
         std::string("Failed to create filter graph: ") + filterArgs.str() +
         ": " + getFFMPEGErrorStringFromErrorCode(ffmpegStatus));
   }
 
   ffmpegStatus = avfilter_graph_create_filter(
-      &filterState.sinkContext,
+      &filterGraphContext.sinkContext,
       buffersink,
       "out",
       nullptr,
       nullptr,
-      filterState.filterGraph.get());
+      filterGraphContext.filterGraph.get());
   if (ffmpegStatus < 0) {
     throw std::runtime_error(
         "Failed to create filter graph: " +
@@ -388,7 +388,7 @@ void VideoDecoder::createFilterGraph(
   enum AVPixelFormat pix_fmts[] = {AV_PIX_FMT_RGB24, AV_PIX_FMT_NONE};
 
   ffmpegStatus = av_opt_set_int_list(
-      filterState.sinkContext,
+      filterGraphContext.sinkContext,
       "pix_fmts",
       pix_fmts,
       AV_PIX_FMT_NONE,
@@ -403,11 +403,11 @@ void VideoDecoder::createFilterGraph(
   UniqueAVFilterInOut inputs(avfilter_inout_alloc());
 
   outputs->name = av_strdup("in");
-  outputs->filter_ctx = filterState.sourceContext;
+  outputs->filter_ctx = filterGraphContext.sourceContext;
   outputs->pad_idx = 0;
   outputs->next = nullptr;
   inputs->name = av_strdup("out");
-  inputs->filter_ctx = filterState.sinkContext;
+  inputs->filter_ctx = filterGraphContext.sinkContext;
   inputs->pad_idx = 0;
   inputs->next = nullptr;
 
@@ -418,7 +418,7 @@ void VideoDecoder::createFilterGraph(
   AVFilterInOut* outputsTmp = outputs.release();
   AVFilterInOut* inputsTmp = inputs.release();
   ffmpegStatus = avfilter_graph_parse_ptr(
-      filterState.filterGraph.get(),
+      filterGraphContext.filterGraph.get(),
       description.str().c_str(),
       &inputsTmp,
       &outputsTmp,
@@ -431,7 +431,8 @@ void VideoDecoder::createFilterGraph(
         getFFMPEGErrorStringFromErrorCode(ffmpegStatus));
   }
 
-  ffmpegStatus = avfilter_graph_config(filterState.filterGraph.get(), nullptr);
+  ffmpegStatus =
+      avfilter_graph_config(filterGraphContext.filterGraph.get(), nullptr);
   if (ffmpegStatus < 0) {
     throw std::runtime_error(
         "Failed to configure filter graph: " +
@@ -1057,7 +1058,7 @@ void VideoDecoder::convertAVFrameToFrameOutputOnCPU(
   } else if (
       streamInfo.colorConversionLibrary ==
       ColorConversionLibrary::FILTERGRAPH) {
-    if (!streamInfo.filterState.filterGraph ||
+    if (!streamInfo.filterGraphContext.filterGraph ||
         streamInfo.prevFrameContext != frameContext) {
       createFilterGraph(streamInfo, expectedOutputHeight, expectedOutputWidth);
       streamInfo.prevFrameContext = frameContext;
@@ -1615,16 +1616,17 @@ int VideoDecoder::convertAVFrameToTensorUsingSwsScale(
 torch::Tensor VideoDecoder::convertAVFrameToTensorUsingFilterGraph(
     int streamIndex,
     const AVFrame* avFrame) {
-  FilterState& filterState = streamInfos_[streamIndex].filterState;
+  FilterGraphContext& filterGraphContext =
+      streamInfos_[streamIndex].filterGraphContext;
   int ffmpegStatus =
-      av_buffersrc_write_frame(filterState.sourceContext, avFrame);
+      av_buffersrc_write_frame(filterGraphContext.sourceContext, avFrame);
   if (ffmpegStatus < AVSUCCESS) {
     throw std::runtime_error("Failed to add frame to buffer source context");
   }
 
   UniqueAVFrame filteredAVFrame(av_frame_alloc());
-  ffmpegStatus =
-      av_buffersink_get_frame(filterState.sinkContext, filteredAVFrame.get());
+  ffmpegStatus = av_buffersink_get_frame(
+      filterGraphContext.sinkContext, filteredAVFrame.get());
   TORCH_CHECK_EQ(filteredAVFrame->format, AV_PIX_FMT_RGB24);
 
   auto frameDims = getHeightAndWidthFromResizedAVFrame(*filteredAVFrame.get());

src/torchcodec/decoders/_core/VideoDecoder.h

@@ -293,7 +293,7 @@ class VideoDecoder {
     int64_t nextPts = INT64_MAX;
   };
 
-  struct FilterState {
+  struct FilterGraphContext {
     UniqueAVFilterGraph filterGraph;
     AVFilterContext* sourceContext = nullptr;
     AVFilterContext* sinkContext = nullptr;
@@ -325,7 +325,7 @@ class VideoDecoder {
     VideoStreamOptions videoStreamOptions;
     // The filter state associated with this stream (for video streams). The
     // actual graph will be nullptr for inactive streams.
-    FilterState filterState;
+    FilterGraphContext filterGraphContext;
     ColorConversionLibrary colorConversionLibrary = FILTERGRAPH;
     std::vector<FrameInfo> keyFrames;
     std::vector<FrameInfo> allFrames;