aacenc: create and initialize an LTP context

This commit only creates and initializes an LTP
context which is needed for upcoming commits (TNS).

Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>

libavcodec/aacenc.c

@@ -676,6 +676,7 @@ static av_cold int aac_encode_end(AVCodecContext *avctx)
     ff_mdct_end(&s->mdct1024);
     ff_mdct_end(&s->mdct128);
     ff_psy_end(&s->psy);
+    ff_lpc_end(&s->lpc);
     if (s->psypp)
         ff_psy_preprocess_end(s->psypp);
     av_freep(&s->buffer.samples);
@@ -775,6 +776,7 @@ static av_cold int aac_encode_init(AVCodecContext *avctx)
         goto fail;
     s->psypp = ff_psy_preprocess_init(avctx);
     s->coder = &ff_aac_coders[s->options.aac_coder];
+    ff_lpc_init(&s->lpc, avctx->frame_size, TNS_MAX_ORDER, FF_LPC_TYPE_LEVINSON);
 
     if (HAVE_MIPSDSPR1)
         ff_aac_coder_init_mips(s);

libavcodec/aacenc.h

@@ -30,6 +30,8 @@
 #include "audio_frame_queue.h"
 #include "psymodel.h"
 
+#include "lpc.h"
+
 typedef enum AACCoder {
     AAC_CODER_FAAC = 0,
     AAC_CODER_ANMR,
@@ -75,6 +77,7 @@ typedef struct AACEncContext {
     AVFloatDSPContext *fdsp;
     float *planar_samples[6];                    ///< saved preprocessed input
 
+    LPCContext lpc;                              ///< used by TNS
     int samplerate_index;                        ///< MPEG-4 samplerate index
     int channels;                                ///< channel count
     const uint8_t *chan_map;                     ///< channel configuration map