Remove glog and try making ffmpeg finding more robust

Author: fmassa

setup.py

@@ -7,6 +7,7 @@
 from pkg_resources import get_distribution, DistributionNotFound
 import subprocess
 import distutils.command.clean
+import distutils.spawn
 import glob
 import shutil
 
@@ -135,8 +136,9 @@ def get_extensions():
 
     # Packages install by conda will put header files in the include folder of
     # conda virtual environment
-    conda_prefix = os.environ.get('CONDA_PREFIX')
-    conda_include_dir = os.path.join(conda_prefix, 'include')
+    ffmpeg_bin = os.path.dirname(distutils.spawn.find_executable('ffmpeg'))
+    ffmpeg_root = os.path.dirname(ffmpeg_bin)
+    ffmpeg_include_dir = os.path.join(ffmpeg_root, 'include')
 
     # TorchVision video reader
     video_reader_src_dir = os.path.join(this_dir, 'torchvision', 'csrc', 'cpu', 'video_reader')
@@ -169,10 +171,10 @@ def get_extensions():
             video_reader_src,
             include_dirs=[
                 video_reader_src_dir,
-                conda_include_dir,
+                ffmpeg_include_dir,
+                extensions_dir,
             ],
             libraries=[
-                'glog',
                 'avcodec',
                 'avformat',
                 'avutil',

torchvision/csrc/cpu/video_reader/FfmpegUtil.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <string>
+#include <array>
 #include "FfmpegHeaders.h"
 #include "Interface.h"
 

torchvision/csrc/cpu/video_reader/Interface.h

@@ -1,6 +1,6 @@
 #pragma once
 
-#include <glog/logging.h>
+#include <c10/util/Logging.h>
 #include <sys/types.h>
 #include <memory>
 #include <unordered_map>

torchvision/csrc/cpu/video_reader/VideoReader.cpp

@@ -1,6 +1,6 @@
 #include "VideoReader.h"
 #include <ATen/ATen.h>
-#include <glog/logging.h>
+#include <c10/util/Logging.h>
 #include <exception>
 #include "FfmpegDecoder.h"
 #include "FfmpegHeaders.h"
@@ -152,7 +152,7 @@ torch::List<torch::Tensor> readVideo(
     int64_t audioTimeBaseDen) {
   if (!glog_initialized) {
     glog_initialized = true;
-    google::InitGoogleLogging("VideoReader");
+    // google::InitGoogleLogging("VideoReader");
   }
 
   unique_ptr<DecoderParameters> params = util::getDecoderParams(