avcodec/mpeg12enc: return more specific error codes for encode_init()

Signed-off-by: Limin Wang <lance.lmwang@gmail.com>

libavcodec/mpeg12enc.c

@@ -139,16 +139,17 @@ static int find_frame_rate_index(MpegEncContext *s)
 
 static av_cold int encode_init(AVCodecContext *avctx)
 {
+    int ret;
     MpegEncContext *s = avctx->priv_data;
 
-    if (ff_mpv_encode_init(avctx) < 0)
-        return -1;
+    if ((ret = ff_mpv_encode_init(avctx)) < 0)
+        return ret;
 
     if (find_frame_rate_index(s) < 0) {
         if (s->strict_std_compliance > FF_COMPLIANCE_EXPERIMENTAL) {
             av_log(avctx, AV_LOG_ERROR, "MPEG-1/2 does not support %d/%d fps\n",
                    avctx->time_base.den, avctx->time_base.num);
-            return -1;
+            return AVERROR(EINVAL);
         } else {
             av_log(avctx, AV_LOG_INFO,
                    "MPEG-1/2 does not support %d/%d fps, there may be AV sync issues\n",
@@ -159,7 +160,7 @@ static av_cold int encode_init(AVCodecContext *avctx)
     if (avctx->profile == FF_PROFILE_UNKNOWN) {
         if (avctx->level != FF_LEVEL_UNKNOWN) {
             av_log(avctx, AV_LOG_ERROR, "Set profile and level\n");
-            return -1;
+            return AVERROR(EINVAL);
         }
         /* Main or 4:2:2 */
         avctx->profile = s->chroma_format == CHROMA_420 ? FF_PROFILE_MPEG2_MAIN : FF_PROFILE_MPEG2_422;
@@ -175,7 +176,7 @@ static av_cold int encode_init(AVCodecContext *avctx)
             if (avctx->profile != FF_PROFILE_MPEG2_HIGH && s->chroma_format != CHROMA_420) {
                 av_log(avctx, AV_LOG_ERROR,
                        "Only High(1) and 4:2:2(0) profiles support 4:2:2 color sampling\n");
-                return -1;
+                return AVERROR(EINVAL);
             }
             if (avctx->width <= 720 && avctx->height <= 576)
                 avctx->level = 8;                   /* Main */
@@ -205,7 +206,7 @@ static av_cold int encode_init(AVCodecContext *avctx)
     if (s->drop_frame_timecode && s->frame_rate_index != 4) {
         av_log(avctx, AV_LOG_ERROR,
                "Drop frame time code only allowed with 1001/30000 fps\n");
-        return -1;
+        return AVERROR(EINVAL);
     }
 
 #if FF_API_PRIVATE_OPT