lavc: Move start code finding to utils.c

This allows dropping the mpegvideo dependency from a number of
components.

This also fixes standalone building of the h264 parser, which
was broken in 64e438697.

Signed-off-by: Martin Storsjö <martin@martin.st>

configure

@@ -1514,7 +1514,7 @@ atrac1_decoder_select="mdct sinewin"
 atrac3_decoder_select="mdct"
 binkaudio_dct_decoder_select="mdct rdft dct sinewin"
 binkaudio_rdft_decoder_select="mdct rdft sinewin"
-cavs_decoder_select="golomb h264chroma mpegvideo videodsp"
+cavs_decoder_select="golomb h264chroma videodsp"
 comfortnoise_encoder_select="lpc"
 cook_decoder_select="mdct sinewin"
 cscd_decoder_select="lzo"
@@ -1752,13 +1752,12 @@ mov_demuxer_suggest="zlib"
 mov_muxer_select="rtpenc_chain"
 mp3_demuxer_select="mpegaudio_parser"
 mp4_muxer_select="mov_muxer"
-mpegts_muxer_select="adts_muxer latm_muxer mpegvideo"
+mpegts_muxer_select="adts_muxer latm_muxer"
 mpegtsraw_demuxer_select="mpegts_demuxer"
 mxf_d10_muxer_select="mxf_muxer"
 ogg_demuxer_select="golomb"
 psp_muxer_select="mov_muxer"
 rtp_demuxer_select="sdp_demuxer"
-rtp_muxer_select="mpegvideo"
 rtpdec_select="asf_demuxer rm_demuxer rtp_protocol mpegts_demuxer mov_demuxer"
 rtsp_demuxer_select="http_protocol rtpdec"
 rtsp_muxer_select="rtp_muxer http_protocol rtp_protocol rtpenc_chain"

libavcodec/mpegvideo.c

@@ -158,39 +158,6 @@ static void mpeg_er_decode_mb(void *opaque, int ref, int mv_dir, int mv_type,
     ff_MPV_decode_mb(s, s->block);
 }
 
-const uint8_t *avpriv_mpv_find_start_code(const uint8_t *restrict p,
-                                          const uint8_t *end,
-                                          uint32_t * restrict state)
-{
-    int i;
-
-    assert(p <= end);
-    if (p >= end)
-        return end;
-
-    for (i = 0; i < 3; i++) {
-        uint32_t tmp = *state << 8;
-        *state = tmp + *(p++);
-        if (tmp == 0x100 || p == end)
-            return p;
-    }
-
-    while (p < end) {
-        if      (p[-1] > 1      ) p += 3;
-        else if (p[-2]          ) p += 2;
-        else if (p[-3]|(p[-1]-1)) p++;
-        else {
-            p++;
-            break;
-        }
-    }
-
-    p = FFMIN(p, end) - 4;
-    *state = AV_RB32(p);
-
-    return p + 4;
-}
-
 /* init common dct for both encoder and decoder */
 av_cold int ff_dct_common_init(MpegEncContext *s)
 {

libavcodec/utils.c

@@ -39,6 +39,7 @@
 #include "avcodec.h"
 #include "dsputil.h"
 #include "libavutil/opt.h"
+#include "mpegvideo.h"
 #include "thread.h"
 #include "internal.h"
 #include "bytestream.h"
@@ -2197,3 +2198,36 @@ int avcodec_is_open(AVCodecContext *s)
 {
     return !!s->internal;
 }
+
+const uint8_t *avpriv_mpv_find_start_code(const uint8_t *restrict p,
+                                          const uint8_t *end,
+                                          uint32_t * restrict state)
+{
+    int i;
+
+    assert(p <= end);
+    if (p >= end)
+        return end;
+
+    for (i = 0; i < 3; i++) {
+        uint32_t tmp = *state << 8;
+        *state = tmp + *(p++);
+        if (tmp == 0x100 || p == end)
+            return p;
+    }
+
+    while (p < end) {
+        if      (p[-1] > 1      ) p += 3;
+        else if (p[-2]          ) p += 2;
+        else if (p[-3]|(p[-1]-1)) p++;
+        else {
+            p++;
+            break;
+        }
+    }
+
+    p = FFMIN(p, end) - 4;
+    *state = AV_RB32(p);
+
+    return p + 4;
+}