sbc: add parser for SBC

1 files changed, 122 insertions, 0 deletions

diff --git a/libavcodec/sbc_parser.c b/libavcodec/sbc_parser.c
new file mode 100644
index 0000000000..f56564147a
--- /dev/null
+++ b/libavcodec/sbc_parser.c
@@ -0,0 +1,122 @@
+/*
+ * SBC parser
+ *
+ * Copyright (C) 2017  Aurelien Jacobs <aurel@gnuage.org>
+ *
+ * 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
+ */
+
+#include "sbc.h"
+#include "parser.h"
+
+typedef struct SBCParseContext {
+    ParseContext pc;
+    uint8_t header[3];
+    int header_size;
+    int buffered_size;
+} SBCParseContext;
+
+static int sbc_parse_header(AVCodecParserContext *s, AVCodecContext *avctx,
+                            const uint8_t *data, size_t len)
+{
+    static const int sample_rates[4] = { 16000, 32000, 44100, 48000 };
+    int sr, blocks, mode, subbands, bitpool, channels, joint;
+    int length;
+
+    if (len < 3)
+        return -1;
+
+    if (data[0] == MSBC_SYNCWORD && data[1] == 0 && data[2] == 0) {
+        avctx->channels = 1;
+        avctx->sample_fmt = AV_SAMPLE_FMT_S16;
+        avctx->sample_rate = 16000;
+        avctx->frame_size = 120;
+        s->duration = avctx->frame_size;
+        return 57;
+    }
+
+    if (data[0] != SBC_SYNCWORD)
+        return -2;
+
+    sr       =   (data[1] >> 6) & 0x03;
+    blocks   = (((data[1] >> 4) & 0x03) + 1) << 2;
+    mode     =   (data[1] >> 2) & 0x03;
+    subbands = (((data[1] >> 0) & 0x01) + 1) << 2;
+    bitpool  = data[2];
+
+    channels = mode == SBC_MODE_MONO ? 1 : 2;
+    joint    = mode == SBC_MODE_JOINT_STEREO;
+
+    length = 4 + (subbands * channels) / 2
+             + ((((mode == SBC_MODE_DUAL_CHANNEL) + 1) * blocks * bitpool
+                 + (joint * subbands)) + 7) / 8;
+
+    avctx->channels = channels;
+    avctx->sample_fmt = AV_SAMPLE_FMT_S16;
+    avctx->sample_rate = sample_rates[sr];
+    avctx->frame_size = subbands * blocks;
+    s->duration = avctx->frame_size;
+    return length;
+}
+
+static int sbc_parse(AVCodecParserContext *s, AVCodecContext *avctx,
+                     const uint8_t **poutbuf, int *poutbuf_size,
+                     const uint8_t *buf, int buf_size)
+{
+    SBCParseContext *pc = s->priv_data;
+    int next;
+
+    if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
+        next = buf_size;
+    } else {
+        if (pc->header_size) {
+            memcpy(pc->header + pc->header_size, buf,
+                   sizeof(pc->header) - pc->header_size);
+            next = sbc_parse_header(s, avctx, pc->header, sizeof(pc->header))
+                 - pc->buffered_size;
+            pc->header_size = 0;
+        } else {
+            next = sbc_parse_header(s, avctx, buf, buf_size);
+            if (next >= buf_size)
+                next = -1;
+        }
+
+        if (next < 0) {
+            pc->header_size = FFMIN(sizeof(pc->header), buf_size);
+            memcpy(pc->header, buf, pc->header_size);
+            pc->buffered_size = buf_size;
+            next = END_NOT_FOUND;
+        }
+
+        if (ff_combine_frame(&pc->pc, next, &buf, &buf_size) < 0) {
+            *poutbuf      = NULL;
+            *poutbuf_size = 0;
+            return buf_size;
+        }
+    }
+
+    *poutbuf      = buf;
+    *poutbuf_size = buf_size;
+    return next;
+}
+
+AVCodecParser ff_sbc_parser = {
+    .codec_ids      = { AV_CODEC_ID_SBC },
+    .priv_data_size = sizeof(SBCParseContext),
+    .parser_parse   = sbc_parse,
+    .parser_close   = ff_parse_close,
+};