lavc/libaribb24: add a default style that has correct PlayResX/Y

As well as font size.

Author: jeeb

libavcodec/libaribb24.c

@@ -44,17 +44,83 @@ static void libaribb24_log(void *p, const char *msg)
     av_log((AVCodecContext *)p, AV_LOG_INFO, "%s\n", msg);
 }
 
+static int libaribb24_generate_ass_header(AVCodecContext *avctx)
+{
+    unsigned int plane_width = 0;
+    unsigned int plane_height = 0;
+    unsigned int font_size = 0;
+
+    switch (avctx->profile) {
+    case FF_PROFILE_ARIB_PROFILE_A:
+        plane_width = 960;
+        plane_height = 540;
+        font_size = 36;
+        break;
+    case FF_PROFILE_ARIB_PROFILE_C:
+        plane_width = 320;
+        plane_height = 180;
+        font_size = 18;
+        break;
+    default:
+        av_log(avctx, AV_LOG_ERROR, "Unknown or unsupported profile set!\n");
+        return AVERROR(EINVAL);
+    }
+
+    avctx->subtitle_header = av_asprintf(
+             "[Script Info]\r\n"
+             "; Script generated by FFmpeg/Lavc%s\r\n"
+             "ScriptType: v4.00+\r\n"
+             "PlayResX: %d\r\n"
+             "PlayResY: %d\r\n"
+             "\r\n"
+             "[V4+ Styles]\r\n"
+
+             /* ASSv4 header */
+             "Format: Name, "
+             "Fontname, Fontsize, "
+             "PrimaryColour, SecondaryColour, OutlineColour, BackColour, "
+             "Bold, Italic, Underline, StrikeOut, "
+             "ScaleX, ScaleY, "
+             "Spacing, Angle, "
+             "BorderStyle, Outline, Shadow, "
+             "Alignment, MarginL, MarginR, MarginV, "
+             "Encoding\r\n"
+
+             "Style: "
+             "Default,"             /* Name */
+             "%s,%d,"               /* Font{name,size} */
+             "&H%x,&H%x,&H%x,&H%x," /* {Primary,Secondary,Outline,Back}Colour */
+             "%d,%d,%d,0,"          /* Bold, Italic, Underline, StrikeOut */
+             "100,100,"             /* Scale{X,Y} */
+             "0,0,"                 /* Spacing, Angle */
+             "%d,1,0,"              /* BorderStyle, Outline, Shadow */
+             "%d,10,10,10,"         /* Alignment, Margin[LRV] */
+             "0\r\n"                /* Encoding */
+
+             "\r\n"
+             "[Events]\r\n"
+             "Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text\r\n",
+             !(avctx->flags & AV_CODEC_FLAG_BITEXACT) ? AV_STRINGIFY(LIBAVCODEC_VERSION) : "",
+             plane_width, plane_height,
+             ASS_DEFAULT_FONT, font_size, ASS_DEFAULT_COLOR,
+             ASS_DEFAULT_COLOR, ASS_DEFAULT_BACK_COLOR, ASS_DEFAULT_BACK_COLOR,
+             -ASS_DEFAULT_BOLD, -ASS_DEFAULT_ITALIC, -ASS_DEFAULT_UNDERLINE,
+             ASS_DEFAULT_BORDERSTYLE, ASS_DEFAULT_ALIGNMENT);
+
+    if (!avctx->subtitle_header)
+        return AVERROR(ENOMEM);
+
+    avctx->subtitle_header_size = strlen(avctx->subtitle_header);
+
+    return 0;
+}
+
 static int libaribb24_init(AVCodecContext *avctx)
 {
     Libaribb24Context *b24 = avctx->priv_data;
     void(* arib_dec_init)(arib_decoder_t* decoder) = NULL;
     int ret_code = AVERROR_EXTERNAL;
 
-    if (ff_ass_subtitle_header_default(avctx) < 0) {
-        ret_code = AVERROR(ENOMEM);
-        goto init_fail;
-    }
-
     if (!(b24->lib_instance = arib_instance_new(avctx))) {
         av_log(avctx, AV_LOG_ERROR, "Failed to initialize libaribb24!\n");
         goto init_fail;
@@ -92,6 +158,11 @@ static int libaribb24_init(AVCodecContext *avctx)
 
     arib_dec_init(b24->decoder);
 
+    if (libaribb24_generate_ass_header(avctx) < 0) {
+        ret_code = AVERROR(ENOMEM);
+        goto init_fail;
+    }
+
     return 0;
 
 init_fail: