deps/media-playback: Fix bug where inverted media would crash

When media returns frames with negative linesizes, it means they're
inverted RGB formats and start from the last line of the image and move
back to the top via the negative linesize number.  This would cause a
crash because this wasn't being taken in to account, and it would
traverse in to invalid memory.

deps/media-playback/media-playback/media.c

@@ -289,6 +289,7 @@ static void mp_media_next_video(mp_media_t *m, bool preload)
 		return;
 	}
 
+	bool flip = false;
 	if (m->swscale) {
 		int ret = sws_scale(m->swscale,
 				(const uint8_t *const *)f->data, f->linesize,
@@ -297,17 +298,24 @@ static void mp_media_next_video(mp_media_t *m, bool preload)
 		if (ret < 0)
 			return;
 
+		flip = m->scale_linesizes[0] < 0 && m->scale_linesizes[1] == 0;
 		for (size_t i = 0; i < 4; i++) {
 			frame->data[i] = m->scale_pic[i];
-			frame->linesize[i] = m->scale_linesizes[i];
+			frame->linesize[i] = abs(m->scale_linesizes[i]);
 		}
+
 	} else {
+		flip = f->linesize[0] < 0 && f->linesize[1] == 0;
+
 		for (size_t i = 0; i < MAX_AV_PLANES; i++) {
 			frame->data[i] = f->data[i];
-			frame->linesize[i] = f->linesize[i];
+			frame->linesize[i] = abs(f->linesize[i]);
 		}
 	}
 
+	if (flip)
+		frame->data[0] -= frame->linesize[0] * (f->height - 1);
+
 	new_format = convert_pixel_format(m->scale_format);
 	new_space  = convert_color_space(f->colorspace);
 	new_range  = m->force_range == VIDEO_RANGE_DEFAULT
@@ -346,7 +354,7 @@ static void mp_media_next_video(mp_media_t *m, bool preload)
 		m->play_sys_ts - base_sys_ts;
 	frame->width = f->width;
 	frame->height = f->height;
-	frame->flip = false;
+	frame->flip = flip;
 
 	if (preload)
 		m->v_preload_cb(m->opaque, frame);