Add support for iLBC decoding/encoding via the external library libilbc

The library is 3-clause BSD licensed.
Signed-off-by: Martin Storsjö <martin@martin.st>

Changelog

@@ -26,6 +26,7 @@ version <next>:
 - Indeo Audio decoder
 - channelsplit audio filter
 - RTMPT protocol support
+- iLBC encoding/decoding via libilbc
 
 
 version 0.8:

configure

@@ -172,6 +172,7 @@ External library support:
   --enable-libfaac         enable FAAC support via libfaac [no]
   --enable-libfreetype     enable libfreetype [no]
   --enable-libgsm          enable GSM support via libgsm [no]
+  --enable-libilbc         enable iLBC de/encoding via libilbc [no]
   --enable-libmp3lame      enable MP3 encoding via libmp3lame [no]
   --enable-libopencore-amrnb enable AMR-NB de/encoding via libopencore-amrnb [no]
   --enable-libopencore-amrwb enable AMR-WB decoding via libopencore-amrwb [no]
@@ -945,6 +946,7 @@ CONFIG_LIST="
     libfaac
     libfreetype
     libgsm
+    libilbc
     libmp3lame
     libopencore_amrnb
     libopencore_amrwb
@@ -1427,6 +1429,8 @@ libgsm_decoder_deps="libgsm"
 libgsm_encoder_deps="libgsm"
 libgsm_ms_decoder_deps="libgsm"
 libgsm_ms_encoder_deps="libgsm"
+libilbc_decoder_deps="libilbc"
+libilbc_encoder_deps="libilbc"
 libmp3lame_encoder_deps="libmp3lame"
 libopencore_amrnb_decoder_deps="libopencore_amrnb"
 libopencore_amrnb_encoder_deps="libopencore_amrnb"
@@ -2917,6 +2921,7 @@ enabled gnutls     && require_pkg_config gnutls gnutls/gnutls.h gnutls_global_in
 enabled libfaac    && require2 libfaac "stdint.h faac.h" faacEncGetVersion -lfaac
 enabled libfreetype && require_pkg_config freetype2 "ft2build.h freetype/freetype.h" FT_Init_FreeType
 enabled libgsm     && require  libgsm gsm/gsm.h gsm_create -lgsm
+enabled libilbc    && require  libilbc ilbc.h WebRtcIlbcfix_InitDecode -lilbc
 enabled libmp3lame && require  "libmp3lame >= 3.98.3" lame/lame.h lame_set_VBR_quality -lmp3lame
 enabled libopencore_amrnb  && require libopencore_amrnb opencore-amrnb/interf_dec.h Decoder_Interface_init -lopencore-amrnb
 enabled libopencore_amrwb  && require libopencore_amrwb opencore-amrwb/dec_if.h D_IF_init -lopencore-amrwb
@@ -3206,6 +3211,7 @@ echo "libcdio support           ${libcdio-no}"
 echo "libdc1394 support         ${libdc1394-no}"
 echo "libfaac enabled           ${libfaac-no}"
 echo "libgsm enabled            ${libgsm-no}"
+echo "libilbc enabled           ${libilbc-no}"
 echo "libmp3lame enabled        ${libmp3lame-no}"
 echo "libopencore-amrnb support ${libopencore_amrnb-no}"
 echo "libopencore-amrwb support ${libopencore_amrwb-no}"

doc/general.texi

@@ -85,6 +85,17 @@ x264 is under the GNU Public License Version 2 or later
 details), you must upgrade Libav's license to GPL in order to use it.
 @end float
 
+@section libilbc
+
+iLBC is a narrowband speech codec that has been made freely available
+by Google as part of the WebRTC project. libilbc is a packaging friendly
+copy of the iLBC codec. Libav can make use of the libilbc library for
+iLBC encoding and decoding.
+
+Go to @url{https://github.com/dekkers/libilbc} and follow the instructions for
+installing the library. Then pass @code{--enable-libilbc} to configure to
+enable it.
+
 
 
 @chapter Supported File Formats and Codecs
@@ -707,6 +718,8 @@ following image formats are supported:
 @item GSM Microsoft variant  @tab  E  @tab  X
     @tab encoding supported through external library libgsm
 @item IAC (Indeo Audio Coder)  @tab     @tab  X
+@item iLBC (Internet Low Bitrate Codec) @tab  E  @tab  E
+    @tab encoding and decoding supported through external library libilbc
 @item IMC (Intel Music Coder)  @tab     @tab  X
 @item MACE (Macintosh Audio Compression/Expansion) 3:1  @tab     @tab  X
 @item MACE (Macintosh Audio Compression/Expansion) 6:1  @tab     @tab  X

libavcodec/Makefile

@@ -596,6 +596,8 @@ OBJS-$(CONFIG_LIBGSM_DECODER)             += libgsm.o
 OBJS-$(CONFIG_LIBGSM_ENCODER)             += libgsm.o
 OBJS-$(CONFIG_LIBGSM_MS_DECODER)          += libgsm.o
 OBJS-$(CONFIG_LIBGSM_MS_ENCODER)          += libgsm.o
+OBJS-$(CONFIG_LIBILBC_DECODER)            += libilbc.o
+OBJS-$(CONFIG_LIBILBC_ENCODER)            += libilbc.o
 OBJS-$(CONFIG_LIBMP3LAME_ENCODER)         += libmp3lame.o mpegaudiodecheader.o \
                                              audio_frame_queue.o
 OBJS-$(CONFIG_LIBOPENCORE_AMRNB_DECODER)  += libopencore-amr.o

libavcodec/allcodecs.c

@@ -379,6 +379,7 @@ void avcodec_register_all(void)
     REGISTER_ENCODER (LIBFAAC, libfaac);
     REGISTER_ENCDEC  (LIBGSM, libgsm);
     REGISTER_ENCDEC  (LIBGSM_MS, libgsm_ms);
+    REGISTER_ENCDEC  (LIBILBC, libilbc);
     REGISTER_ENCODER (LIBMP3LAME, libmp3lame);
     REGISTER_ENCDEC  (LIBOPENCORE_AMRNB, libopencore_amrnb);
     REGISTER_DECODER (LIBOPENCORE_AMRWB, libopencore_amrwb);

libavcodec/avcodec.h

@@ -394,6 +394,7 @@ enum CodecID {
     CODEC_ID_BMV_AUDIO,
     CODEC_ID_RALF,
     CODEC_ID_IAC,
+    CODEC_ID_ILBC,
 
     /* subtitle codecs */
     CODEC_ID_FIRST_SUBTITLE = 0x17000,          ///< A dummy ID pointing at the start of subtitle codecs.

libavcodec/libilbc.c

+/*
+ * iLBC decoder/encoder stub
+ * Copyright (c) 2012 Martin Storsjo
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <ilbc.h>
+
+#include "avcodec.h"
+#include "libavutil/opt.h"
+#include "internal.h"
+
+static int get_mode(AVCodecContext *avctx)
+{
+    if (avctx->block_align == 38)
+        return 20;
+    else if (avctx->block_align == 50)
+        return 30;
+    else if (avctx->bit_rate > 0)
+        return avctx->bit_rate <= 14000 ? 30 : 20;
+    else
+        return -1;
+}
+
+typedef struct ILBCDecContext {
+    const AVClass *class;
+    AVFrame frame;
+    iLBC_Dec_Inst_t decoder;
+    int enhance;
+} ILBCDecContext;
+
+static const AVOption ilbc_dec_options[] = {
+    { "enhance", "Enhance the decoded audio (adds delay)", offsetof(ILBCDecContext, enhance), AV_OPT_TYPE_INT, { 0 }, 0, 1, AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_DECODING_PARAM },
+    { NULL }
+};
+
+static const AVClass ilbc_dec_class = {
+    "libilbc", av_default_item_name, ilbc_dec_options, LIBAVUTIL_VERSION_INT
+};
+
+static av_cold int ilbc_decode_init(AVCodecContext *avctx)
+{
+    ILBCDecContext *s  = avctx->priv_data;
+    int mode;
+
+    if ((mode = get_mode(avctx)) < 0) {
+        av_log(avctx, AV_LOG_ERROR, "iLBC frame mode not indicated\n");
+        return AVERROR(EINVAL);
+    }
+
+    WebRtcIlbcfix_InitDecode(&s->decoder, mode, s->enhance);
+    avcodec_get_frame_defaults(&s->frame);
+    avctx->coded_frame = &s->frame;
+
+    avctx->channels = 1;
+    avctx->sample_rate = 8000;
+    avctx->sample_fmt = AV_SAMPLE_FMT_S16;
+
+    return 0;
+}
+
+static int ilbc_decode_frame(AVCodecContext *avctx, void *data,
+                             int *got_frame_ptr, AVPacket *avpkt)
+{
+    const uint8_t *buf = avpkt->data;
+    int buf_size       = avpkt->size;
+    ILBCDecContext *s  = avctx->priv_data;
+    int ret;
+
+    if (s->decoder.no_of_bytes > buf_size) {
+        av_log(avctx, AV_LOG_ERROR, "iLBC frame too short (%u, should be %u)\n",
+               buf_size, s->decoder.no_of_bytes);
+        return AVERROR_INVALIDDATA;
+    }
+
+    s->frame.nb_samples = s->decoder.blockl;
+    if ((ret = avctx->get_buffer(avctx, &s->frame)) < 0) {
+        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
+        return ret;
+    }
+
+    WebRtcIlbcfix_DecodeImpl((WebRtc_Word16*) s->frame.data[0],
+                             (const WebRtc_UWord16*) buf, &s->decoder, 1);
+
+    *got_frame_ptr   = 1;
+    *(AVFrame *)data = s->frame;
+
+    return s->decoder.no_of_bytes;
+}
+
+AVCodec ff_libilbc_decoder = {
+    .name           = "libilbc",
+    .type           = AVMEDIA_TYPE_AUDIO,
+    .id             = CODEC_ID_ILBC,
+    .priv_data_size = sizeof(ILBCDecContext),
+    .init           = ilbc_decode_init,
+    .decode         = ilbc_decode_frame,
+    .capabilities   = CODEC_CAP_DR1,
+    .long_name      = NULL_IF_CONFIG_SMALL("Internet Low Bitrate Codec (iLBC)"),
+    .priv_class     = &ilbc_dec_class,
+};
+
+typedef struct ILBCEncContext {
+    const AVClass *class;
+    iLBC_Enc_Inst_t encoder;
+    int mode;
+} ILBCEncContext;
+
+static const AVOption ilbc_enc_options[] = {
+    { "mode", "iLBC mode (20 or 30 ms frames)", offsetof(ILBCEncContext, mode), AV_OPT_TYPE_INT, { 20 }, 20, 30, AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM },
+    { NULL }
+};
+
+static const AVClass ilbc_enc_class = {
+    "libilbc", av_default_item_name, ilbc_enc_options, LIBAVUTIL_VERSION_INT
+};
+
+static av_cold int ilbc_encode_init(AVCodecContext *avctx)
+{
+    ILBCEncContext *s = avctx->priv_data;
+    int mode;
+
+    if (avctx->sample_rate != 8000) {
+        av_log(avctx, AV_LOG_ERROR, "Only 8000Hz sample rate supported\n");
+        return AVERROR(EINVAL);
+    }
+
+    if (avctx->channels != 1) {
+        av_log(avctx, AV_LOG_ERROR, "Only mono supported\n");
+        return AVERROR(EINVAL);
+    }
+
+    if ((mode = get_mode(avctx)) > 0)
+        s->mode = mode;
+    else
+        s->mode = s->mode != 30 ? 20 : 30;
+    WebRtcIlbcfix_InitEncode(&s->encoder, s->mode);
+
+    avctx->block_align = s->encoder.no_of_bytes;
+    avctx->frame_size  = s->encoder.blockl;
+#if FF_API_OLD_ENCODE_AUDIO
+    avctx->coded_frame = avcodec_alloc_frame();
+    if (!avctx->coded_frame)
+        return AVERROR(ENOMEM);
+#endif
+
+    return 0;
+}
+
+static av_cold int ilbc_encode_close(AVCodecContext *avctx)
+{
+#if FF_API_OLD_ENCODE_AUDIO
+    av_freep(&avctx->coded_frame);
+#endif
+    return 0;
+}
+
+static int ilbc_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
+                             const AVFrame *frame, int *got_packet_ptr)
+{
+    ILBCEncContext *s = avctx->priv_data;
+    int ret;
+
+    if ((ret = ff_alloc_packet(avpkt, 50))) {
+        av_log(avctx, AV_LOG_ERROR, "Error getting output packet\n");
+        return ret;
+    }
+
+    WebRtcIlbcfix_EncodeImpl((WebRtc_UWord16*) avpkt->data, (const WebRtc_Word16*) frame->data[0], &s->encoder);
+
+    avpkt->size     = s->encoder.no_of_bytes;
+    *got_packet_ptr = 1;
+    return 0;
+}
+
+static const AVCodecDefault ilbc_encode_defaults[] = {
+    { "b", "0" },
+    { NULL }
+};
+
+AVCodec ff_libilbc_encoder = {
+    .name           = "libilbc",
+    .type           = AVMEDIA_TYPE_AUDIO,
+    .id             = CODEC_ID_ILBC,
+    .priv_data_size = sizeof(ILBCEncContext),
+    .init           = ilbc_encode_init,
+    .encode2        = ilbc_encode_frame,
+    .close          = ilbc_encode_close,
+    .sample_fmts    = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
+                                                     AV_SAMPLE_FMT_NONE },
+    .long_name      = NULL_IF_CONFIG_SMALL("Internet Low Bitrate Codec (iLBC)"),
+    .defaults       = ilbc_encode_defaults,
+    .priv_class     = &ilbc_enc_class,
+};

libavcodec/utils.c

@@ -1832,6 +1832,11 @@ int av_get_audio_frame_duration(AVCodecContext *avctx, int frame_bytes)
             case 29: return 288;
             case 37: return 480;
             }
+        } else if (id == CODEC_ID_ILBC) {
+            switch (ba) {
+            case 38: return 160;
+            case 50: return 240;
+            }
         }
     }
 

libavcodec/version.h

@@ -27,7 +27,7 @@
  */
 
 #define LIBAVCODEC_VERSION_MAJOR 54
-#define LIBAVCODEC_VERSION_MINOR 14
+#define LIBAVCODEC_VERSION_MINOR 15
 #define LIBAVCODEC_VERSION_MICRO  0
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \