Restructure the video/video_reader C++ codebase (#3311)

* Moving registration of video methods in Video.cpp and removing unnecessary includes.

* Rename files according to cpp styles.

* Adding namespaces and moving private methods to anonymous namespaces.

* Syncing method names.

* Fixing minor issues.

torchvision/csrc/io/video/register.cpp

-#include "Video.h"
-
-namespace {
-
-static auto registerVideo =
-    torch::class_<Video>("torchvision", "Video")
-        .def(torch::init<std::string, std::string>())
-        .def("get_current_stream", &Video::getCurrentStream)
-        .def("set_current_stream", &Video::setCurrentStream)
-        .def("get_metadata", &Video::getStreamMetadata)
-        .def("seek", &Video::Seek)
-        .def("next", &Video::Next);
-
-} // namespace

torchvision/csrc/io/video/Video.cpp → torchvision/csrc/io/video/video.cpp

-#include "Video.h"
-#include <c10/util/Logging.h>
-#include <torch/script.h>
-#include "defs.h"
-#include "memory_buffer.h"
-#include "sync_decoder.h"
+#include "video.h"
 
-using namespace std;
-using namespace ffmpeg;
+#include <regex>
+
+namespace vision {
+namespace video {
+
+namespace {
 
 const size_t decoderTimeoutMs = 600000;
 const AVPixelFormat defaultVideoPixelFormat = AV_PIX_FMT_RGB24;
@@ -93,6 +92,8 @@ std::tuple<std::string, long> _parseStream(const std::string& streamString) {
   return std::make_tuple(type_, index_);
 }
 
+} // namespace
+
 void Video::_getDecoderParams(
     double videoStartS,
     int64_t getPtsOnly,
@@ -159,7 +160,7 @@ Video::Video(std::string videoPath, std::string stream) {
   Video::_getDecoderParams(
       0, // video start
       0, // headerOnly
-      get<0>(current_stream), // stream info - remove that
+      std::get<0>(current_stream), // stream info - remove that
       long(-1), // stream_id parsed from info above change to -2
       true // read all streams
   );
@@ -209,9 +210,9 @@ Video::Video(std::string videoPath, std::string stream) {
 
   succeeded = Video::setCurrentStream(stream);
   LOG(INFO) << "\nDecoder inited with: " << succeeded << "\n";
-  if (get<1>(current_stream) != -1) {
+  if (std::get<1>(current_stream) != -1) {
     LOG(INFO)
-        << "Stream index set to " << get<1>(current_stream)
+        << "Stream index set to " << std::get<1>(current_stream)
         << ". If you encounter trouble, consider switching it to automatic stream discovery. \n";
   }
 } // video
@@ -229,8 +230,8 @@ bool Video::setCurrentStream(std::string stream = "video") {
   _getDecoderParams(
       ts, // video start
       0, // headerOnly
-      get<0>(current_stream), // stream
-      long(get<1>(
+      std::get<0>(current_stream), // stream
+      long(std::get<1>(
           current_stream)), // stream_id parsed from info above change to -2
       false // read all streams
   );
@@ -253,8 +254,8 @@ void Video::Seek(double ts) {
   _getDecoderParams(
       ts, // video start
       0, // headerOnly
-      get<0>(current_stream), // stream
-      long(get<1>(
+      std::get<0>(current_stream), // stream
+      long(std::get<1>(
           current_stream)), // stream_id parsed from info above change to -2
       false // read all streams
   );
@@ -319,3 +320,15 @@ std::tuple<torch::Tensor, double> Video::Next() {
 
   return std::make_tuple(outFrame, frame_pts_s);
 }
+
+static auto registerVideo =
+    torch::class_<Video>("torchvision", "Video")
+        .def(torch::init<std::string, std::string>())
+        .def("get_current_stream", &Video::getCurrentStream)
+        .def("set_current_stream", &Video::setCurrentStream)
+        .def("get_metadata", &Video::getStreamMetadata)
+        .def("seek", &Video::Seek)
+        .def("next", &Video::Next);
+
+} // namespace video
+} // namespace vision

torchvision/csrc/io/video/Video.h → torchvision/csrc/io/video/video.h

 #pragma once
 
-#include <map>
-#include <regex>
-#include <string>
-#include <vector>
+#include <torch/types.h>
 
-#include <ATen/ATen.h>
-#include <c10/util/Logging.h>
-#include <torch/script.h>
-
-#include <exception>
-#include "defs.h"
-#include "memory_buffer.h"
-#include "sync_decoder.h"
+#include "../decoder/defs.h"
+#include "../decoder/memory_buffer.h"
+#include "../decoder/sync_decoder.h"
 
 using namespace ffmpeg;
 
+namespace vision {
+namespace video {
+
 struct Video : torch::CustomClassHolder {
   std::tuple<std::string, long> current_stream; // stream type, id
   // global video metadata
@@ -58,3 +53,6 @@ struct Video : torch::CustomClassHolder {
   DecoderParameters params;
 
 }; // struct Video
+
+} // namespace video
+} // namespace vision

torchvision/csrc/io/video_reader/VideoReader.h

-#pragma once
-
-#include <torch/script.h>

torchvision/csrc/io/video_reader/VideoReader.cpp → torchvision/csrc/io/video_reader/video_reader.cpp

-#include "VideoReader.h"
-#include <ATen/ATen.h>
+#include "video_reader.h"
+
 #include <Python.h>
-#include <c10/util/Logging.h>
-#include <exception>
-#include "memory_buffer.h"
-#include "sync_decoder.h"
 
-using namespace std;
-using namespace ffmpeg;
+#include "../decoder/memory_buffer.h"
+#include "../decoder/sync_decoder.h"
 
 // If we are in a Windows environment, we need to define
 // initialization functions for the _custom_ops extension
@@ -18,8 +14,13 @@ PyMODINIT_FUNC PyInit_video_reader(void) {
 }
 #endif
 
+using namespace ffmpeg;
+
+namespace vision {
 namespace video_reader {
 
+namespace {
+
 const AVPixelFormat defaultVideoPixelFormat = AV_PIX_FMT_RGB24;
 const AVSampleFormat defaultAudioSampleFormat = AV_SAMPLE_FMT_FLT;
 const AVRational timeBaseQ = AVRational{1, AV_TIME_BASE};
@@ -417,95 +418,6 @@ torch::List<torch::Tensor> readVideo(
   return result;
 }
 
-torch::List<torch::Tensor> readVideoFromMemory(
-    torch::Tensor input_video,
-    double seekFrameMargin,
-    int64_t getPtsOnly,
-    int64_t readVideoStream,
-    int64_t width,
-    int64_t height,
-    int64_t minDimension,
-    int64_t maxDimension,
-    int64_t videoStartPts,
-    int64_t videoEndPts,
-    int64_t videoTimeBaseNum,
-    int64_t videoTimeBaseDen,
-    int64_t readAudioStream,
-    int64_t audioSamples,
-    int64_t audioChannels,
-    int64_t audioStartPts,
-    int64_t audioEndPts,
-    int64_t audioTimeBaseNum,
-    int64_t audioTimeBaseDen) {
-  return readVideo(
-      false,
-      input_video,
-      "", // videoPath
-      seekFrameMargin,
-      getPtsOnly,
-      readVideoStream,
-      width,
-      height,
-      minDimension,
-      maxDimension,
-      videoStartPts,
-      videoEndPts,
-      videoTimeBaseNum,
-      videoTimeBaseDen,
-      readAudioStream,
-      audioSamples,
-      audioChannels,
-      audioStartPts,
-      audioEndPts,
-      audioTimeBaseNum,
-      audioTimeBaseDen);
-}
-
-torch::List<torch::Tensor> readVideoFromFile(
-    std::string videoPath,
-    double seekFrameMargin,
-    int64_t getPtsOnly,
-    int64_t readVideoStream,
-    int64_t width,
-    int64_t height,
-    int64_t minDimension,
-    int64_t maxDimension,
-    int64_t videoStartPts,
-    int64_t videoEndPts,
-    int64_t videoTimeBaseNum,
-    int64_t videoTimeBaseDen,
-    int64_t readAudioStream,
-    int64_t audioSamples,
-    int64_t audioChannels,
-    int64_t audioStartPts,
-    int64_t audioEndPts,
-    int64_t audioTimeBaseNum,
-    int64_t audioTimeBaseDen) {
-  torch::Tensor dummy_input_video = torch::ones({0});
-  return readVideo(
-      true,
-      dummy_input_video,
-      videoPath,
-      seekFrameMargin,
-      getPtsOnly,
-      readVideoStream,
-      width,
-      height,
-      minDimension,
-      maxDimension,
-      videoStartPts,
-      videoEndPts,
-      videoTimeBaseNum,
-      videoTimeBaseDen,
-      readAudioStream,
-      audioSamples,
-      audioChannels,
-      audioStartPts,
-      audioEndPts,
-      audioTimeBaseNum,
-      audioTimeBaseDen);
-}
-
 torch::List<torch::Tensor> probeVideo(
     bool isReadFile,
     const torch::Tensor& input_video,
@@ -650,20 +562,112 @@ torch::List<torch::Tensor> probeVideo(
   return result;
 }
 
-torch::List<torch::Tensor> probeVideoFromMemory(torch::Tensor input_video) {
+} // namespace
+
+torch::List<torch::Tensor> read_video_from_memory(
+    torch::Tensor input_video,
+    double seekFrameMargin,
+    int64_t getPtsOnly,
+    int64_t readVideoStream,
+    int64_t width,
+    int64_t height,
+    int64_t minDimension,
+    int64_t maxDimension,
+    int64_t videoStartPts,
+    int64_t videoEndPts,
+    int64_t videoTimeBaseNum,
+    int64_t videoTimeBaseDen,
+    int64_t readAudioStream,
+    int64_t audioSamples,
+    int64_t audioChannels,
+    int64_t audioStartPts,
+    int64_t audioEndPts,
+    int64_t audioTimeBaseNum,
+    int64_t audioTimeBaseDen) {
+  return readVideo(
+      false,
+      input_video,
+      "", // videoPath
+      seekFrameMargin,
+      getPtsOnly,
+      readVideoStream,
+      width,
+      height,
+      minDimension,
+      maxDimension,
+      videoStartPts,
+      videoEndPts,
+      videoTimeBaseNum,
+      videoTimeBaseDen,
+      readAudioStream,
+      audioSamples,
+      audioChannels,
+      audioStartPts,
+      audioEndPts,
+      audioTimeBaseNum,
+      audioTimeBaseDen);
+}
+
+torch::List<torch::Tensor> read_video_from_file(
+    std::string videoPath,
+    double seekFrameMargin,
+    int64_t getPtsOnly,
+    int64_t readVideoStream,
+    int64_t width,
+    int64_t height,
+    int64_t minDimension,
+    int64_t maxDimension,
+    int64_t videoStartPts,
+    int64_t videoEndPts,
+    int64_t videoTimeBaseNum,
+    int64_t videoTimeBaseDen,
+    int64_t readAudioStream,
+    int64_t audioSamples,
+    int64_t audioChannels,
+    int64_t audioStartPts,
+    int64_t audioEndPts,
+    int64_t audioTimeBaseNum,
+    int64_t audioTimeBaseDen) {
+  torch::Tensor dummy_input_video = torch::ones({0});
+  return readVideo(
+      true,
+      dummy_input_video,
+      videoPath,
+      seekFrameMargin,
+      getPtsOnly,
+      readVideoStream,
+      width,
+      height,
+      minDimension,
+      maxDimension,
+      videoStartPts,
+      videoEndPts,
+      videoTimeBaseNum,
+      videoTimeBaseDen,
+      readAudioStream,
+      audioSamples,
+      audioChannels,
+      audioStartPts,
+      audioEndPts,
+      audioTimeBaseNum,
+      audioTimeBaseDen);
+}
+
+torch::List<torch::Tensor> probe_video_from_memory(torch::Tensor input_video) {
   return probeVideo(false, input_video, "");
 }
 
-torch::List<torch::Tensor> probeVideoFromFile(std::string videoPath) {
+torch::List<torch::Tensor> probe_video_from_file(std::string videoPath) {
   torch::Tensor dummy_input_video = torch::ones({0});
   return probeVideo(true, dummy_input_video, videoPath);
 }
 
-} // namespace video_reader
-
 TORCH_LIBRARY_FRAGMENT(video_reader, m) {
-  m.def("read_video_from_memory", video_reader::readVideoFromMemory);
-  m.def("read_video_from_file", video_reader::readVideoFromFile);
-  m.def("probe_video_from_memory", video_reader::probeVideoFromMemory);
-  m.def("probe_video_from_file", video_reader::probeVideoFromFile);
+  m.def("read_video_from_memory", read_video_from_memory);
+  m.def("read_video_from_file", read_video_from_file);
+  m.def("probe_video_from_memory", probe_video_from_memory);
+  m.def("probe_video_from_file", probe_video_from_file);
 }
+
+} // namespace video_reader
+} // namespace vision

torchvision/csrc/io/video_reader/video_reader.h

+#pragma once
+
+#include <torch/types.h>
+
+namespace vision {
+namespace video_reader {
+
+torch::List<torch::Tensor> read_video_from_memory(
+    torch::Tensor input_video,
+    double seekFrameMargin,
+    int64_t getPtsOnly,
+    int64_t readVideoStream,
+    int64_t width,
+    int64_t height,
+    int64_t minDimension,
+    int64_t maxDimension,
+    int64_t videoStartPts,
+    int64_t videoEndPts,
+    int64_t videoTimeBaseNum,
+    int64_t videoTimeBaseDen,
+    int64_t readAudioStream,
+    int64_t audioSamples,
+    int64_t audioChannels,
+    int64_t audioStartPts,
+    int64_t audioEndPts,
+    int64_t audioTimeBaseNum,
+    int64_t audioTimeBaseDen);
+
+torch::List<torch::Tensor> read_video_from_file(
+    std::string videoPath,
+    double seekFrameMargin,
+    int64_t getPtsOnly,
+    int64_t readVideoStream,
+    int64_t width,
+    int64_t height,
+    int64_t minDimension,
+    int64_t maxDimension,
+    int64_t videoStartPts,
+    int64_t videoEndPts,
+    int64_t videoTimeBaseNum,
+    int64_t videoTimeBaseDen,
+    int64_t readAudioStream,
+    int64_t audioSamples,
+    int64_t audioChannels,
+    int64_t audioStartPts,
+    int64_t audioEndPts,
+    int64_t audioTimeBaseNum,
+    int64_t audioTimeBaseDen);
+
+torch::List<torch::Tensor> probe_video_from_memory(torch::Tensor input_video);
+
+torch::List<torch::Tensor> probe_video_from_file(std::string videoPath);
+
+} // namespace video_reader
+} // namespace vision