1 files changed, 97 insertions, 0 deletions
diff --git a/contrib/ffmpeg/libavcodec/libgsm.c b/contrib/ffmpeg/libavcodec/libgsm.c
new file mode 100644
index 000000000..7cf59be7a
--- /dev/null
+++ b/contrib/ffmpeg/libavcodec/libgsm.c
@@ -0,0 +1,97 @@
+/*
+ * Interface to libgsm for gsm encoding/decoding
+ * Copyright (c) 2005 Alban Bedel <albeu@free.fr>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file libgsm.c
+ * Interface to libgsm for gsm encoding/decoding
+ */
+
+#include "avcodec.h"
+#include <gsm.h>
+
+// gsm.h miss some essential constants
+#define GSM_BLOCK_SIZE 33
+#define GSM_FRAME_SIZE 160
+
+static int libgsm_init(AVCodecContext *avctx) {
+    if (avctx->channels > 1 || avctx->sample_rate != 8000)
+        return -1;
+
+    avctx->frame_size = GSM_FRAME_SIZE;
+    avctx->block_align = GSM_BLOCK_SIZE;
+
+    avctx->priv_data = gsm_create();
+
+    avctx->coded_frame= avcodec_alloc_frame();
+    avctx->coded_frame->key_frame= 1;
+
+    return 0;
+}
+
+static int libgsm_close(AVCodecContext *avctx) {
+    gsm_destroy(avctx->priv_data);
+    avctx->priv_data = NULL;
+    return 0;
+}
+
+static int libgsm_encode_frame(AVCodecContext *avctx,
+                               unsigned char *frame, int buf_size, void *data) {
+    // we need a full block
+    if(buf_size < GSM_BLOCK_SIZE) return 0;
+
+    gsm_encode(avctx->priv_data,data,frame);
+
+    return GSM_BLOCK_SIZE;
+}
+
+
+AVCodec libgsm_encoder = {
+    "gsm",
+    CODEC_TYPE_AUDIO,
+    CODEC_ID_GSM,
+    0,
+    libgsm_init,
+    libgsm_encode_frame,
+    libgsm_close,
+};
+
+static int libgsm_decode_frame(AVCodecContext *avctx,
+                               void *data, int *data_size,
+                               uint8_t *buf, int buf_size) {
+
+    if(buf_size < GSM_BLOCK_SIZE) return 0;
+
+    if(gsm_decode(avctx->priv_data,buf,data)) return -1;
+
+    *data_size = GSM_FRAME_SIZE*2;
+    return GSM_BLOCK_SIZE;
+}
+
+AVCodec libgsm_decoder = {
+    "gsm",
+    CODEC_TYPE_AUDIO,
+    CODEC_ID_GSM,
+    0,
+    libgsm_init,
+    NULL,
+    libgsm_close,
+    libgsm_decode_frame,
+};