avcodec/mjpegenc: Add wrapper for ff_mjpeg_encode_picture_header()

This factors the translation from MpegEncContext out
and will enable further optimizations in the next commits.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavcodec/mjpegenc.c

@@ -74,6 +74,19 @@ static av_cold void init_uni_ac_vlc(const uint8_t huff_size_ac[256],
     }
 }
 
+static void mjpeg_encode_picture_header(MpegEncContext *s)
+{
+    ff_mjpeg_encode_picture_header(s->avctx, &s->pb, &s->intra_scantable,
+                                   s->pred, s->intra_matrix, s->chroma_intra_matrix);
+}
+
+void ff_mjpeg_amv_encode_picture_header(MpegEncContext *s)
+{
+    /* s->huffman == HUFFMAN_TABLE_OPTIMAL can only be true for MJPEG. */
+    if (!CONFIG_MJPEG_ENCODER || s->huffman != HUFFMAN_TABLE_OPTIMAL)
+        mjpeg_encode_picture_header(s);
+}
+
 #if CONFIG_MJPEG_ENCODER
 /**
  * Encodes and outputs the entire frame in the JPEG format.
@@ -213,8 +226,7 @@ int ff_mjpeg_encode_stuffing(MpegEncContext *s)
         s->intra_chroma_ac_vlc_length      =
         s->intra_chroma_ac_vlc_last_length = m->uni_chroma_ac_vlc_len;
 
-        ff_mjpeg_encode_picture_header(s->avctx, &s->pb, &s->intra_scantable,
-                                       s->pred, s->intra_matrix, s->chroma_intra_matrix);
+        mjpeg_encode_picture_header(s);
         mjpeg_encode_picture_frame(s);
     }
 #endif

libavcodec/mjpegenc.h

@@ -105,6 +105,7 @@ static inline void put_marker(PutBitContext *p, enum JpegMarker code)
 }
 
 int  ff_mjpeg_encode_init(MpegEncContext *s);
+void ff_mjpeg_amv_encode_picture_header(MpegEncContext *s);
 void ff_mjpeg_encode_mb(MpegEncContext *s, int16_t block[12][64]);
 int  ff_mjpeg_encode_stuffing(MpegEncContext *s);
 

libavcodec/mpegvideo_enc.c

@@ -3702,10 +3702,7 @@ static int encode_picture(MpegEncContext *s, int picture_number)
     switch(s->out_format) {
 #if CONFIG_MJPEG_ENCODER || CONFIG_AMV_ENCODER
     case FMT_MJPEG:
-        /* s->huffman == HUFFMAN_TABLE_OPTIMAL can only be true for MJPEG. */
-        if (!CONFIG_MJPEG_ENCODER || s->huffman != HUFFMAN_TABLE_OPTIMAL)
-            ff_mjpeg_encode_picture_header(s->avctx, &s->pb, &s->intra_scantable,
-                                           s->pred, s->intra_matrix, s->chroma_intra_matrix);
+        ff_mjpeg_amv_encode_picture_header(s);
         break;
 #endif
     case FMT_SPEEDHQ: