ffmpeg deprecation cleanup: substitute AVPicture with AVFrame

See https://github.com/FFmpeg/FFmpeg/blob/n4.4.3/libavcodec/avpicture.c#L40
for the original implementation of the function substituted

src/devices/ffmpeg/FfmpegGrabber.cpp

@@ -119,7 +119,6 @@ class DecoderState
     {
         // Get a pointer to the codec context for the video stream
         pCodecCtx=pFormatCtx->streams[index]->codec;
-
         // Find the decoder for the video stream
         pCodec = avcodec_find_decoder(pFormatCtx->streams[index]->codecpar->codec_id);
         if(pCodec==nullptr) {
@@ -150,13 +149,13 @@ class DecoderState
         }
 
         // Determine required buffer size and allocate buffer
-        int numBytes=avpicture_get_size(AV_PIX_FMT_RGB24, pCodecCtx->width,
-                                        pCodecCtx->height);
+        int numBytes=av_image_get_buffer_size(AV_PIX_FMT_RGB24, pCodecCtx->width,
+                                              pCodecCtx->height, 1);
         buffer=new uint8_t[numBytes];
 
         // Assign appropriate parts of buffer to image planes in pFrameRGB
-        avpicture_fill((AVPicture *)pFrameRGB, buffer, AV_PIX_FMT_RGB24,
-                       pCodecCtx->width, pCodecCtx->height);
+        av_image_fill_arrays(pFrameRGB->data, pFrameRGB->linesize, buffer,
+                             AV_PIX_FMT_RGB24, pCodecCtx->width, pCodecCtx->height, 1);
         return true;
     }
 
@@ -270,11 +269,11 @@ class DecoderState
                                                  nullptr, nullptr, nullptr);
             }
             if (img_convert_ctx!=nullptr) {
-                sws_scale(img_convert_ctx, ((AVPicture*)pFrame)->data,
-                          ((AVPicture*)pFrame)->linesize, 0,
+                sws_scale(img_convert_ctx, pFrame->data,
+                          pFrame->linesize, 0,
                           pCodecCtx->height,
-                          ((AVPicture*)pFrameRGB)->data,
-                          ((AVPicture*)pFrameRGB)->linesize);
+                          pFrameRGB->data,
+                          pFrameRGB->linesize);
             } else {
                 yCFatal(FFMPEGGRABBER, "Software scaling not working");
             }

src/devices/ffmpeg/FfmpegWriter.cpp

@@ -391,14 +391,14 @@ static AVFrame *alloc_picture(int pix_fmt, int width, int height)
     if (!picture) {
         return nullptr;
     }
-    size = avpicture_get_size((AVPixelFormat)pix_fmt, width, height);
+    size = av_image_get_buffer_size((AVPixelFormat)pix_fmt, width, height, 1);
     picture_buf = (uint8_t*)av_malloc(size);
     if (!picture_buf) {
         av_free(picture);
         return nullptr;
     }
-    avpicture_fill((AVPicture *)picture, picture_buf,
-                   (AVPixelFormat)pix_fmt, width, height);
+    av_image_fill_arrays(picture->data, picture->linesize, picture_buf,
+                   (AVPixelFormat)pix_fmt, width, height,1);
     return picture;
 }
 
@@ -475,8 +475,8 @@ void FfmpegWriter::write_video_frame(AVFormatContext *oc, AVStream *st,
 
     if (c->pix_fmt != AV_PIX_FMT_RGB24) {
         fill_rgb_image(tmp_picture, frame_count, c->width, c->height, img);
-        stable_img_convert((AVPicture *)picture, c->pix_fmt,
-                           (AVPicture *)tmp_picture, AV_PIX_FMT_RGB24,
+        stable_img_convert(picture, c->pix_fmt,
+                           tmp_picture, AV_PIX_FMT_RGB24,
                            c->width, c->height);
     } else {
         fill_rgb_image(picture, frame_count, c->width, c->height, img);

src/devices/ffmpeg/ffmpeg_api.cpp

@@ -7,8 +7,8 @@
 #include "ffmpeg_api.h"
 
 
-int stable_img_convert (AVPicture *dst, int dst_pix_fmt,
-                        const AVPicture *src, int src_pix_fmt,
+int stable_img_convert (AVFrame *dst, int dst_pix_fmt,
+                        const AVFrame *src, int src_pix_fmt,
                         int src_width, int src_height) {
   static struct SwsContext *img_convert_ctx = nullptr;
   if (img_convert_ctx==nullptr) {
@@ -26,16 +26,16 @@ int stable_img_convert (AVPicture *dst, int dst_pix_fmt,
       /*
       printf("software scale: %ld %ld/%ld %d/%d %d\n",
              (long int)img_convert_ctx,
-             (long int)(((AVPicture*)src)->data),
-             (long int)(((AVPicture*)dst)->data),
-             ((AVPicture*)src)->linesize[0],
-             ((AVPicture*)dst)->linesize[0],
+             (long int)(src->data),
+             (long int)(dst->data),
+             src->linesize[0],
+             dst->linesize[0],
              src_height);
       */
 
-      sws_scale(img_convert_ctx, ((AVPicture*)src)->data,
-                ((AVPicture*)src)->linesize, 0, src_height,
-                ((AVPicture*)dst)->data, ((AVPicture*)dst)->linesize);
+      sws_scale(img_convert_ctx, src->data,
+                src->linesize, 0, src_height,
+                dst->data, dst->linesize);
       //printf("software scale done\n");
   } else {
     fprintf(stderr,"image conversion failed\n");

src/devices/ffmpeg/ffmpeg_api.h

@@ -41,8 +41,9 @@ extern "C" {
 #  define av_dict_set_int(x, k, v, f) { char buf[256]; sprintf(buf,"%d",v); av_dict_set(x, k ,buf, 0); }
 #endif
 
-int stable_img_convert (AVPicture *dst, int dst_pix_fmt,
-                        const AVPicture *src, int src_pix_fmt,
+
+int stable_img_convert (AVFrame *dst, int dst_pix_fmt,
+                        const AVFrame *src, int src_pix_fmt,
                         int src_width, int src_height);