[fbsync] Fix build with ffmpeg 6.0 (pytorch#8096)

Summary: Signed-off-by: Zoltán Böszörményi <zboszor@gmail.com>

Reviewed By: vmoens

Differential Revision: D55062796

fbshipit-source-id: ebd3bd552ee55f1bc2788df64ed21ed4fefab09e

Co-authored-by: Nicolas Hug <nh.nicolas.hug@gmail.com>
(cherry picked from commit 152bad7)

torchvision/csrc/cpu/decoder/stream.cpp

@@ -62,15 +62,8 @@ int Stream::openCodec(std::vector<DecoderMetadata>* metadata, int num_threads) {
     codecCtx_->thread_count = num_threads;
   } else {
     // otherwise set sensible defaults
-    // with the special case for the different MPEG4 codecs
-    // that don't have threading context functions
-    if (codecCtx_->codec->capabilities & AV_CODEC_CAP_INTRA_ONLY) {
-      codecCtx_->thread_type = FF_THREAD_FRAME;
-      codecCtx_->thread_count = 2;
-    } else {
-      codecCtx_->thread_count = 8;
-      codecCtx_->thread_type = FF_THREAD_SLICE;
-    }
+    codecCtx_->thread_count = 8;
+    codecCtx_->thread_type = FF_THREAD_SLICE;
   }
 
   // print codec type and number of threads