lame: Use libav wrapper to encode mp3lame

Fixes https://forum.handbrake.fr/viewtopic.php?f=12&t=33345
Some players expect each packet to start on an mp3 frame header. Our
mp3lame encoder did not ensure this and resulted in failure to play
audio on these players.

libav already has the necessary code to parse headers and
accumulate a full frame of data, so use it.

Author: jstebbins

contrib/ffmpeg/module.defs

@@ -27,12 +27,14 @@ FFMPEG.CONFIGURE.extra = \
     --disable-network \
     --disable-hwaccels \
     --disable-encoders \
+    --enable-libmp3lame \
     --enable-encoder=aac \
     --enable-encoder=ac3 \
     --enable-encoder=eac3 \
     --enable-encoder=flac \
     --enable-encoder=mpeg2video \
     --enable-encoder=mpeg4 \
+    --enable-encoder=libmp3lame \
     --enable-libvpx \
     --enable-encoder=libvpx_vp8 \
     --disable-decoder=libvpx_vp8 \

libhb/common.h

@@ -1163,7 +1163,6 @@ extern hb_work_object_t hb_encx265;
 extern hb_work_object_t hb_decavcodeca;
 extern hb_work_object_t hb_decavcodecv;
 extern hb_work_object_t hb_declpcm;
-extern hb_work_object_t hb_enclame;
 extern hb_work_object_t hb_encvorbis;
 extern hb_work_object_t hb_muxer;
 extern hb_work_object_t hb_encca_aac;

libhb/encavcodecaudio.c

@@ -121,6 +121,10 @@ static int encavcodecaInit(hb_work_object_t *w, hb_job_t *job)
             }
             break;
 
+        case HB_ACODEC_LAME:
+            codec_name = "libmp3lame";
+            break;
+
         default:
             hb_error("encavcodecaInit: unsupported codec (0x%x)",
                      audio->config.out.codec);

libhb/enclame.c

@@ -1677,7 +1677,6 @@ int hb_global_init()
     hb_register(&hb_encca_aac);
     hb_register(&hb_encca_haac);
 #endif
-    hb_register(&hb_enclame);
     hb_register(&hb_enctheora);
     hb_register(&hb_encvorbis);
     hb_register(&hb_encx264);

libhb/hb.c

@@ -191,8 +191,8 @@ hb_work_object_t* hb_codec_encoder(hb_handle_t *h, int codec)
     }
     switch (codec)
     {
-        case HB_ACODEC_AC3:     return hb_get_work(h, WORK_ENCAVCODEC_AUDIO);
-        case HB_ACODEC_LAME:    return hb_get_work(h, WORK_ENCLAME);
+        case HB_ACODEC_AC3:
+        case HB_ACODEC_LAME:    return hb_get_work(h, WORK_ENCAVCODEC_AUDIO);
         case HB_ACODEC_VORBIS:  return hb_get_work(h, WORK_ENCVORBIS);
         case HB_ACODEC_CA_AAC:  return hb_get_work(h, WORK_ENC_CA_AAC);
         case HB_ACODEC_CA_HAAC: return hb_get_work(h, WORK_ENC_CA_HAAC);