From fab71806eb954b84a7bdb2bca2d3d2667f2fad1e Mon Sep 17 00:00:00 2001
From: Martin Piatka <piatka@cesnet.cz>
Date: Wed, 11 Aug 2021 14:13:59 +0200
Subject: [PATCH] Lavc: print warning about 422 subsampling hwaccel support

---
 src/libavcodec_common.h           | 16 ++++++++++++++++
 src/video_compress/libavcodec.cpp |  4 ++++
 src/video_decompress/libavcodec.c | 15 +--------------
 3 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/src/libavcodec_common.h b/src/libavcodec_common.h
index d78756db3..759e33df0 100644
--- a/src/libavcodec_common.h
+++ b/src/libavcodec_common.h
@@ -195,6 +195,22 @@ static void print_decoder_error(const char *mod_name, int rc) {
 	}
 }
 
+inline static bool pixfmt_has_422_subsampling(enum AVPixelFormat fmt){
+        const AVPixFmtDescriptor *fmt_desc = av_pix_fmt_desc_get(fmt);
+
+        return fmt_desc && !(fmt_desc->flags & AV_PIX_FMT_FLAG_HWACCEL)
+                && fmt_desc->log2_chroma_w == 1 && fmt_desc->log2_chroma_h == 0;
+}
+
+inline static bool pixfmt_list_has_422_subsasmpling(const enum AVPixelFormat *fmt){
+        for(const enum AVPixelFormat *it = fmt; *it != AV_PIX_FMT_NONE; it++){
+                if(pixfmt_has_422_subsampling(*it))
+                        return true;
+        }
+
+        return false;
+}
+
 void print_libav_error(int verbosity, const char *msg, int rc);
 bool libav_codec_has_extradata(codec_t codec);
 
diff --git a/src/video_compress/libavcodec.cpp b/src/video_compress/libavcodec.cpp
index 32831e7c3..7a0903cd9 100644
--- a/src/video_compress/libavcodec.cpp
+++ b/src/video_compress/libavcodec.cpp
@@ -1242,6 +1242,10 @@ static bool configure_with(struct state_video_compress_libav *s, struct video_de
 
         log_msg(LOG_LEVEL_INFO, "[lavc] Selected pixfmt: %s\n", av_get_pix_fmt_name(pix_fmt));
         s->selected_pixfmt = pix_fmt;
+        if(pixfmt_has_422_subsampling(pix_fmt)){
+                log_msg(LOG_LEVEL_WARNING, "[lavc] Selected pixfmt has 4:2:2 subsampling, "
+                                "which is usually not supported by hw. decoders\n");
+        }
 
         if(!find_decoder(desc, s->selected_pixfmt, &s->decoded_codec, &s->decoder)){
                 log_msg(LOG_LEVEL_ERROR, "[lavc] Failed to find a way to convert %s to %s\n",
diff --git a/src/video_decompress/libavcodec.c b/src/video_decompress/libavcodec.c
index 7f73822ef..dc6a93dd3 100644
--- a/src/video_decompress/libavcodec.c
+++ b/src/video_decompress/libavcodec.c
@@ -494,19 +494,6 @@ fail:
 }
 #endif
 
-static bool is_422_subsasmpling(const enum AVPixelFormat *fmt){
-        for(const enum AVPixelFormat *it = fmt; *it != AV_PIX_FMT_NONE; it++){
-                const AVPixFmtDescriptor *fmt_desc = av_pix_fmt_desc_get(*it);
-                if(!fmt_desc || fmt_desc->flags & AV_PIX_FMT_FLAG_HWACCEL)
-                        continue;
-
-                if(fmt_desc->log2_chroma_w == 1 && fmt_desc->log2_chroma_h == 0)
-                        return true;
-        }
-
-        return false;
-}
-
 static enum AVPixelFormat get_format_callback(struct AVCodecContext *s __attribute__((unused)), const enum AVPixelFormat *fmt)
 {
         if (log_level >= LOG_LEVEL_VERBOSE) {
@@ -542,7 +529,7 @@ static enum AVPixelFormat get_format_callback(struct AVCodecContext *s __attribu
 
         if (hwaccel && state->out_codec != VIDEO_CODEC_NONE) { // not probing internal format
                 struct state_libavcodec_decompress *state = (struct state_libavcodec_decompress *) s->opaque; 
-                if(is_422_subsasmpling(fmt)){
+                if(pixfmt_list_has_422_subsasmpling(fmt)){
                         log_msg(LOG_LEVEL_WARNING, "[lavd] Hw. acceleration requested "
                                         "but incoming video has 4:2:2 subsampling, "
                                         "which is usually not supported by hw. accelerators\n");