@@ -28,6 +28,7 @@ version <next>

 - ffprobe -read_intervals option

 - Lossless and alpha support for WebP decoder

 - Error Resilient AAC syntax (ER AAC LC) decoding

+- Low Delay AAC (ER AAC LD) decoding

 version 2.0:

@@ -290,6 +290,7 @@ struct AACContext {

      */

     FFTContext mdct;

     FFTContext mdct_small;

+    FFTContext mdct_ld;

     FFTContext mdct_ltp;

     FmtConvertContext fmt_conv;

     AVFloatDSPContext fdsp;

@@ -856,6 +856,13 @@ static int decode_audio_specific_config(AACContext *ac,

                m4ac->sampling_index);

         return AVERROR_INVALIDDATA;

     }

+    if (m4ac->object_type == AOT_ER_AAC_LD &&

+        (m4ac->sampling_index < 3 || m4ac->sampling_index > 7)) {

+        av_log(avctx, AV_LOG_ERROR,

+               "invalid low delay sampling rate index %d\n",

+               m4ac->sampling_index);

+        return AVERROR_INVALIDDATA;

+    }

     skip_bits_long(&gb, i);

@@ -864,6 +871,7 @@ static int decode_audio_specific_config(AACContext *ac,

     case AOT_AAC_LC:

     case AOT_AAC_LTP:

     case AOT_ER_AAC_LC:

+    case AOT_ER_AAC_LD:

         if ((ret = decode_ga_specific_config(ac, avctx, &gb,

                                             m4ac, m4ac->chan_config)) < 0)

             return ret;

@@ -1033,12 +1041,15 @@ static av_cold int aac_decode_init(AVCodecContext *avctx)

                     352);

     ff_mdct_init(&ac->mdct,       11, 1, 1.0 / (32768.0 * 1024.0));

+    ff_mdct_init(&ac->mdct_ld,    10, 1, 1.0 / (32768.0 * 512.0));

     ff_mdct_init(&ac->mdct_small,  8, 1, 1.0 / (32768.0 * 128.0));

     ff_mdct_init(&ac->mdct_ltp,   11, 0, -2.0 * 32768.0);

     // window initialization

     ff_kbd_window_init(ff_aac_kbd_long_1024, 4.0, 1024);

+    ff_kbd_window_init(ff_aac_kbd_long_512,  4.0, 512);

     ff_kbd_window_init(ff_aac_kbd_short_128, 6.0, 128);

     ff_init_ff_sine_windows(10);

+    ff_init_ff_sine_windows( 9);

     ff_init_ff_sine_windows( 7);

     cbrt_tableinit();

@@ -1111,6 +1122,14 @@ static int decode_ics_info(AACContext *ac, IndividualChannelStream *ics,

     }

     ics->window_sequence[1] = ics->window_sequence[0];

     ics->window_sequence[0] = get_bits(gb, 2);

+    if (ac->oc[1].m4ac.object_type == AOT_ER_AAC_LD &&

+        ics->window_sequence[0] != ONLY_LONG_SEQUENCE) {

+        av_log(ac->avctx, AV_LOG_ERROR,

+               "AAC LD is only defined for ONLY_LONG_SEQUENCE but "

+               "window sequence %d found.\n", ics->window_sequence[0]);

+        ics->window_sequence[0] = ONLY_LONG_SEQUENCE;

+        return AVERROR_INVALIDDATA;

+    }

     ics->use_kb_window[1]   = ics->use_kb_window[0];

     ics->use_kb_window[0]   = get_bits1(gb);

     ics->num_window_groups  = 1;

@@ -1134,8 +1153,15 @@ static int decode_ics_info(AACContext *ac, IndividualChannelStream *ics,

     } else {

         ics->max_sfb               = get_bits(gb, 6);

         ics->num_windows           = 1;

-        ics->swb_offset            =    ff_swb_offset_1024[ac->oc[1].m4ac.sampling_index];

-        ics->num_swb               =   ff_aac_num_swb_1024[ac->oc[1].m4ac.sampling_index];

+        if (ac->oc[1].m4ac.object_type == AOT_ER_AAC_LD) {

+            ics->swb_offset        =     ff_swb_offset_512[ac->oc[1].m4ac.sampling_index];

+            ics->num_swb           =    ff_aac_num_swb_512[ac->oc[1].m4ac.sampling_index];

+            if (!ics->num_swb || !ics->swb_offset)

+                return AVERROR_BUG;

+        } else {

+            ics->swb_offset        =    ff_swb_offset_1024[ac->oc[1].m4ac.sampling_index];

+            ics->num_swb           =   ff_aac_num_swb_1024[ac->oc[1].m4ac.sampling_index];

+        }

         ics->tns_max_bands         = ff_tns_max_bands_1024[ac->oc[1].m4ac.sampling_index];

         ics->predictor_present     = get_bits1(gb);

         ics->predictor_reset_group = 0;

@@ -1150,6 +1176,11 @@ static int decode_ics_info(AACContext *ac, IndividualChannelStream *ics,

                        "Prediction is not allowed in AAC-LC.\n");

                 goto fail;

             } else {

+                if (ac->oc[1].m4ac.object_type == AOT_ER_AAC_LD) {

+                    av_log(ac->avctx, AV_LOG_ERROR,

+                           "LTP in ER AAC LD not yet implemented.\n");

+                    return AVERROR_PATCHWELCOME;

+                }

                 if ((ics->ltp.present = get_bits(gb, 1)))

                     decode_ltp(&ics->ltp, gb, ics->max_sfb);

             }

@@ -2393,6 +2424,25 @@ static void imdct_and_windowing(AACContext *ac, SingleChannelElement *sce)

     }

 }

+static void imdct_and_windowing_ld(AACContext *ac, SingleChannelElement *sce)

+{

+    IndividualChannelStream *ics = &sce->ics;

+    float *in    = sce->coeffs;

+    float *out   = sce->ret;

+    float *saved = sce->saved;

+    const float *lwindow_prev = ics->use_kb_window[1] ? ff_aac_kbd_long_512 : ff_sine_512;

+    float *buf  = ac->buf_mdct;

+

+    // imdct

+    ac->mdct.imdct_half(&ac->mdct_ld, buf, in);

+

+    // window overlapping

+    ac->fdsp.vector_fmul_window(out, saved, buf, lwindow_prev, 256);

+

+    // buffer update

+    memcpy(saved, buf + 256, 256 * sizeof(float));

+}

+

 /**

  * Apply dependent channel coupling (applied before IMDCT).

  *

@@ -2489,6 +2539,11 @@ static void apply_channel_coupling(AACContext *ac, ChannelElement *cc,

 static void spectral_to_sample(AACContext *ac)

 {

     int i, type;

+    void (*imdct_and_window)(AACContext *ac, SingleChannelElement *sce);

+    if (ac->oc[1].m4ac.object_type == AOT_ER_AAC_LD)

+        imdct_and_window = imdct_and_windowing_ld;

+    else

+        imdct_and_window = ac->imdct_and_windowing;

     for (type = 3; type >= 0; type--) {

         for (i = 0; i < MAX_ELEM_ID; i++) {

             ChannelElement *che = ac->che[type][i];

@@ -2510,11 +2565,11 @@ static void spectral_to_sample(AACContext *ac)

                 if (type <= TYPE_CPE)

                     apply_channel_coupling(ac, che, type, i, BETWEEN_TNS_AND_IMDCT, apply_dependent_coupling);

                 if (type != TYPE_CCE || che->coup.coupling_point == AFTER_IMDCT) {

-                    ac->imdct_and_windowing(ac, &che->ch[0]);

+                    imdct_and_window(ac, &che->ch[0]);

                     if (ac->oc[1].m4ac.object_type == AOT_AAC_LTP)

                         ac->update_ltp(ac, &che->ch[0]);

                     if (type == TYPE_CPE) {

-                        ac->imdct_and_windowing(ac, &che->ch[1]);

+                        imdct_and_window(ac, &che->ch[1]);

                         if (ac->oc[1].m4ac.object_type == AOT_AAC_LTP)

                             ac->update_ltp(ac, &che->ch[1]);

                     }

@@ -2599,6 +2654,9 @@ static int aac_decode_er_frame(AVCodecContext *avctx, void *data,

     int samples = 1024;

     int chan_config = ac->oc[1].m4ac.chan_config;

+    if (ac->oc[1].m4ac.object_type == AOT_ER_AAC_LD)

+        samples >>= 1;

+

     ac->frame = data;

     if ((err = frame_configure_elements(avctx)) < 0)

@@ -2887,6 +2945,7 @@ static av_cold int aac_decode_close(AVCodecContext *avctx)

     ff_mdct_end(&ac->mdct);

     ff_mdct_end(&ac->mdct_small);

+    ff_mdct_end(&ac->mdct_ld);

     ff_mdct_end(&ac->mdct_ltp);

     return 0;

 }

@@ -34,12 +34,17 @@

 #include <stdint.h>

 DECLARE_ALIGNED(32, float,  ff_aac_kbd_long_1024)[1024];

+DECLARE_ALIGNED(32, float,  ff_aac_kbd_long_512 )[512];

 DECLARE_ALIGNED(32, float,  ff_aac_kbd_short_128)[128];

 const uint8_t ff_aac_num_swb_1024[] = {

     41, 41, 47, 49, 49, 51, 47, 47, 43, 43, 43, 40, 40

 };

+const uint8_t ff_aac_num_swb_512[] = {

+     0,  0,  0, 36, 36, 37, 31, 31,  0,  0,  0,  0,  0

+};

+

 const uint8_t ff_aac_num_swb_128[] = {

     12, 12, 12, 14, 14, 14, 15, 15, 15, 15, 15, 15, 15

 };

@@ -1114,6 +1119,14 @@ static const uint16_t swb_offset_1024_48[] = {

     928, 1024

 };

+static const uint16_t swb_offset_512_48[] = {

+      0,   4,   8,  12,  16,  20,  24,  28,

+     32,  36,  40,  44,  48,  52,  56,  60,

+     68,  76,  84,  92, 100, 112, 124, 136,

+    148, 164, 184, 208, 236, 268, 300, 332,

+    364, 396, 428, 460, 512

+};

+

 static const uint16_t swb_offset_128_48[] = {

      0,   4,   8,  12,  16,  20,  28,  36,

     44,  56,  68,  80,  96, 112, 128

@@ -1129,6 +1142,14 @@ static const uint16_t swb_offset_1024_32[] = {

     928, 960, 992, 1024

 };

+static const uint16_t swb_offset_512_32[] = {

+      0,   4,   8,  12,  16,  20,  24,  28,

+     32,  36,  40,  44,  48,  52,  56,  64,

+     72,  80,  88,  96, 108, 120, 132, 144,

+    160, 176, 192, 212, 236, 260, 288, 320,

+    352, 384, 416, 448, 480, 512

+};

+

 static const uint16_t swb_offset_1024_24[] = {

       0,   4,   8,  12,  16,  20,  24,  28,

      32,  36,  40,  44,  52,  60,  68,  76,

@@ -1138,6 +1159,13 @@ static const uint16_t swb_offset_1024_24[] = {

     600, 652, 704, 768, 832, 896, 960, 1024

 };

+static const uint16_t swb_offset_512_24[] = {

+      0,   4,   8,  12,  16,  20,  24,  28,

+     32,  36,  40,  44,  52,  60,  68,  80,

+     92, 104, 120, 140, 164, 192, 224, 256,

+    288, 320, 352, 384, 416, 448, 480, 512,

+};

+

 static const uint16_t swb_offset_128_24[] = {

      0,   4,   8,  12,  16,  20,  24,  28,

     36,  44,  52,  64,  76,  92, 108, 128

@@ -1179,6 +1207,14 @@ const uint16_t * const ff_swb_offset_1024[] = {

     swb_offset_1024_8

 };

+const uint16_t * const ff_swb_offset_512[] = {

+    NULL,               NULL,               NULL,

+    swb_offset_512_48,  swb_offset_512_48,  swb_offset_512_32,

+    swb_offset_512_24,  swb_offset_512_24,  NULL,

+    NULL,               NULL,               NULL,

+    NULL

+};

+

 const uint16_t * const ff_swb_offset_128[] = {

     /* The last entry on the following row is swb_offset_128_64 but is a

        duplicate of swb_offset_128_96. */

@@ -45,6 +45,7 @@

  * @{

  */

 DECLARE_ALIGNED(32, extern float,  ff_aac_kbd_long_1024)[1024];

+DECLARE_ALIGNED(32, extern float,  ff_aac_kbd_long_512 )[512];

 DECLARE_ALIGNED(32, extern float,  ff_aac_kbd_short_128)[128];

 // @}

@@ -52,6 +53,7 @@ DECLARE_ALIGNED(32, extern float,  ff_aac_kbd_short_128)[128];

  * @{

  */

 extern const uint8_t ff_aac_num_swb_1024[];

+extern const uint8_t ff_aac_num_swb_512 [];

 extern const uint8_t ff_aac_num_swb_128 [];

 // @}

@@ -69,6 +71,7 @@ extern const float *ff_aac_codebook_vector_vals[];

 extern const uint16_t *ff_aac_codebook_vector_idx[];

 extern const uint16_t * const ff_swb_offset_1024[13];

+extern const uint16_t * const ff_swb_offset_512 [13];

 extern const uint16_t * const ff_swb_offset_128 [13];

 extern const uint8_t ff_tns_max_bands_1024[13];

@@ -29,7 +29,7 @@

 #include "libavutil/avutil.h"

 #define LIBAVCODEC_VERSION_MAJOR 55

-#define LIBAVCODEC_VERSION_MINOR  32

+#define LIBAVCODEC_VERSION_MINOR  33

 #define LIBAVCODEC_VERSION_MICRO 100

 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \