Loosen dependency on libavcodec

NEWS

@@ -50,4 +50,7 @@ Dependencies
 ------------------------------------------------------------------------------
 
  * GTK+ >= 2.18
- * FFmpeg >= r18351
+ * FFmpeg libraries:
+   * libavcodec
+   * libavformat
+   * libavutil

configure.ac

@@ -24,7 +24,7 @@ AM_PROG_VALAC([0.7.0])
 AC_PROG_INSTALL
 AC_PROG_INTLTOOL([0.35])
 
-pkg_modules="gtk+-2.0 >= 2.18.0 libavformat libavcodec >= 52.23.0 libavutil"
+pkg_modules="gtk+-2.0 >= 2.18.0 libavformat libavcodec libavutil"
 PKG_CHECK_MODULES(SPEK, [$pkg_modules])
 AC_SUBST(SPEK_CFLAGS)
 AC_SUBST(SPEK_LIBS)

src/spek-audio.c

@@ -141,8 +141,14 @@ gint spek_audio_read (SpekAudioContext *cx) {
 	for (;;) {
 		while (cx->packet->size > 0) {
 			buffer_size = cx->buffer_size;
+#if LIBAVCODEC_VERSION_INT >= AV_VERSION_INT (52, 23, 0)
 			len = avcodec_decode_audio3 (
 				cx->codec_context, (int16_t *) cx->buffer, &buffer_size, cx->packet);
+#else
+			len = avcodec_decode_audio2 (
+				cx->codec_context, (int16_t *) cx->buffer, &buffer_size,
+				cx->packet->data, cx->packet->size);
+#endif
 			if (len < 0) {
 				/* Error, skip the frame. */
 				cx->packet->size = 0;