latmenc: copy pce config from proper location.

For the FATE test sample used, this only avoids a warning
message.
However for other samples like al05_44.mp4 the converted
file can be played only after this fix.
Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>

libavformat/latmenc.c

@@ -93,15 +93,12 @@ static void latm_write_frame_header(AVFormatContext *s, PutBitContext *bs)
 {
     LATMContext *ctx = s->priv_data;
     AVCodecContext *avctx = s->streams[0]->codec;
-    GetBitContext gb;
     int header_size;
 
     /* AudioMuxElement */
     put_bits(bs, 1, !!ctx->counter);
 
     if (!ctx->counter) {
-        init_get_bits(&gb, avctx->extradata, avctx->extradata_size * 8);
-
         /* StreamMuxConfig */
         put_bits(bs, 1, 0); /* audioMuxVersion */
         put_bits(bs, 1, 1); /* allStreamsSameTimeFraming */
@@ -117,6 +114,9 @@ static void latm_write_frame_header(AVFormatContext *s, PutBitContext *bs)
             avpriv_copy_bits(bs, avctx->extradata, ctx->off + 3);
 
             if (!ctx->channel_conf) {
+                GetBitContext gb;
+                init_get_bits(&gb, avctx->extradata, avctx->extradata_size * 8);
+                skip_bits_long(&gb, ctx->off + 3);
                 avpriv_copy_pce_data(bs, &gb);
             }
         }

tests/ref/lavf-fate/latm

-9c8d1afdb2d336976102f175ba577471 *./tests/data/lavf-fate/lavf.latm
-71926 ./tests/data/lavf-fate/lavf.latm
-./tests/data/lavf-fate/lavf.latm CRC=0xd846c4b3
+eb13788e71c9b5bc7d62ceb748312bbb *./tests/data/lavf-fate/lavf.latm
+67876 ./tests/data/lavf-fate/lavf.latm
+./tests/data/lavf-fate/lavf.latm CRC=0xcf94c59d