@@ -30,6 +30,7 @@

  * add temporal noise shaping

  ***********************************/

+#include "libavutil/opt.h"

 #include "avcodec.h"

 #include "put_bits.h"

 #include "dsputil.h"

@@ -489,7 +490,7 @@ static int aac_encode_frame(AVCodecContext *avctx,

     AACEncContext *s = avctx->priv_data;

     int16_t *samples = s->samples, *samples2, *la;

     ChannelElement *cpe;

-    int i, ch, w, chans, tag, start_ch;

+    int i, ch, w, g, chans, tag, start_ch;

     const uint8_t *chan_map = aac_chan_configs[avctx->channels-1];

     int chan_el_counter[4];

     FFPsyWindowInfo windows[AAC_MAX_CHANNELS];

@@ -587,8 +588,16 @@ static int aac_encode_frame(AVCodecContext *avctx,

                 }

             }

             s->cur_channel = start_ch;

-            if (cpe->common_window && s->coder->search_for_ms)

-                s->coder->search_for_ms(s, cpe, s->lambda);

+            if (s->options.stereo_mode && cpe->common_window) {

+                if (s->options.stereo_mode > 0) {

+                    IndividualChannelStream *ics = &cpe->ch[0].ics;

+                    for (w = 0; w < ics->num_windows; w += ics->group_len[w])

+                        for (g = 0;  g < ics->num_swb; g++)

+                            cpe->ms_mask[w*16+g] = 1;

+                } else if (s->coder->search_for_ms) {

+                    s->coder->search_for_ms(s, cpe, s->lambda);

+                }

+            }

             adjust_frame_information(s, cpe, chans);

             if (chans == 2) {

                 put_bits(&s->pb, 1, cpe->common_window);

@@ -645,6 +654,22 @@ static av_cold int aac_encode_end(AVCodecContext *avctx)

     return 0;

 }

+#define AACENC_FLAGS AV_OPT_FLAG_ENCODING_PARAM | AV_OPT_FLAG_AUDIO_PARAM

+static const AVOption aacenc_options[] = {

+    {"stereo_mode", "Stereo coding method", offsetof(AACEncContext, options.stereo_mode), FF_OPT_TYPE_INT, {.dbl = 0}, -1, 1, AACENC_FLAGS, "stereo_mode"},

+        {"auto",     "Selected by the Encoder", 0, FF_OPT_TYPE_CONST, {.dbl = -1 }, INT_MIN, INT_MAX, AACENC_FLAGS, "stereo_mode"},

+        {"ms_off",   "Disable Mid/Side coding", 0, FF_OPT_TYPE_CONST, {.dbl =  0 }, INT_MIN, INT_MAX, AACENC_FLAGS, "stereo_mode"},

+        {"ms_force", "Force Mid/Side for the whole frame if possible", 0, FF_OPT_TYPE_CONST, {.dbl =  1 }, INT_MIN, INT_MAX, AACENC_FLAGS, "stereo_mode"},

+    {NULL}

+};

+

+static const AVClass aacenc_class = {

+    "AAC encoder",

+    av_default_item_name,

+    aacenc_options,

+    LIBAVUTIL_VERSION_INT,

+};

+

 AVCodec ff_aac_encoder = {

     "aac",

     AVMEDIA_TYPE_AUDIO,

@@ -656,4 +681,5 @@ AVCodec ff_aac_encoder = {

     .capabilities = CODEC_CAP_SMALL_LAST_FRAME | CODEC_CAP_DELAY | CODEC_CAP_EXPERIMENTAL,

     .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},

     .long_name = NULL_IF_CONFIG_SMALL("Advanced Audio Coding"),

+    .priv_class = &aacenc_class,

 };

@@ -30,6 +30,10 @@

 #include "psymodel.h"

+typedef struct AACEncOptions {

+    int stereo_mode;

+} AACEncOptions;

+

 struct AACEncContext;

 typedef struct AACCoefficientsEncoder {

@@ -48,6 +52,8 @@ extern AACCoefficientsEncoder ff_aac_coders[];

  * AAC encoder context

  */

 typedef struct AACEncContext {

+    AVClass *av_class;

+    AACEncOptions options;                       ///< encoding options

     PutBitContext pb;

     FFTContext mdct1024;                         ///< long (1024 samples) frame transform context

     FFTContext mdct128;                          ///< short (128 samples) frame transform context