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>

1 files changed, 209 insertions, 0 deletions

diff --git a/libavcodec/libilbc.c b/libavcodec/libilbc.c
new file mode 100644
index 0000000000..1c056d5cd7
--- /dev/null
+++ b/libavcodec/libilbc.c
@@ -0,0 +1,209 @@
+/*
+ * 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,
+};