lavf/g726: Demuxer for raw G.726 streams, both left- and right-justified.

Compatible with the binary encoder attached to ticket #6596 (right-aligned)
and a sample from a SEG Mp3-Player (left-aligned).

1 files changed, 105 insertions, 0 deletions

diff --git a/libavformat/g726.c b/libavformat/g726.c
new file mode 100644
index 0000000000..eca9404866
--- /dev/null
+++ b/libavformat/g726.c
@@ -0,0 +1,105 @@
+/*
+ * G.726 raw demuxer
+ * Copyright 2017 Carl Eugen Hoyos
+ *
+ * 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 "avformat.h"
+#include "internal.h"
+#include "libavutil/opt.h"
+
+typedef struct G726Context {
+    AVClass *class;
+    int code_size;
+    int sample_rate;
+} G726Context;
+
+static int g726_read_header(AVFormatContext *s)
+{
+    G726Context *c = s->priv_data;
+    AVStream *st = avformat_new_stream(s, NULL);
+    if (!st)
+        return AVERROR(ENOMEM);
+
+    st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
+    st->codecpar->codec_id   = s->iformat->raw_codec_id;
+
+    st->codecpar->sample_rate           = c->sample_rate;
+    st->codecpar->bits_per_coded_sample = c->code_size;
+    st->codecpar->bit_rate              = ((int[]){ 16000, 24000, 32000, 40000 })[c->code_size - 2];
+    st->codecpar->channels              = 1;
+
+    return 0;
+}
+
+static int g726_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    int res;
+    res = av_get_packet(s->pb, pkt, 1020); // a size similar to RAW_PACKET_SIZE divisible by all code_size values
+    if (res < 0)
+        return res;
+    return 0;
+}
+
+#define OFFSET(x) offsetof(G726Context, x)
+static const AVOption options[] = {
+    { "code_size", "Bits per G.726 code",
+        OFFSET(code_size),   AV_OPT_TYPE_INT, {.i64 =    4}, 2,       5, AV_OPT_FLAG_DECODING_PARAM },
+    { "sample_rate", "",
+        OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64 = 8000}, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
+    { NULL },
+};
+
+#if CONFIG_G726_DEMUXER
+static const AVClass g726le_demuxer_class = {
+    .class_name     = "G.726 big-endian demuxer",
+    .item_name      = av_default_item_name,
+    .option         = options,
+    .version        = LIBAVUTIL_VERSION_INT,
+};
+
+AVInputFormat ff_g726_demuxer = {
+    .name           = "g726",
+    .long_name      = NULL_IF_CONFIG_SMALL("raw big-endian G.726 (\"left aligned\")"),
+    .read_header    = g726_read_header,
+    .read_packet    = g726_read_packet,
+    .priv_data_size = sizeof(G726Context),
+    .priv_class     = &g726le_demuxer_class,
+    .raw_codec_id   = AV_CODEC_ID_ADPCM_G726,
+};
+#endif
+
+#if CONFIG_G726LE_DEMUXER
+static const AVClass g726_demuxer_class = {
+    .class_name     = "G.726 little-endian demuxer",
+    .item_name      = av_default_item_name,
+    .option         = options,
+    .version        = LIBAVUTIL_VERSION_INT,
+};
+
+AVInputFormat ff_g726le_demuxer = {
+    .name           = "g726le",
+    .long_name      = NULL_IF_CONFIG_SMALL("raw little-endian G.726 (\"right aligned\")"),
+    .read_header    = g726_read_header,
+    .read_packet    = g726_read_packet,
+    .priv_data_size = sizeof(G726Context),
+    .priv_class     = &g726_demuxer_class,
+    .raw_codec_id   = AV_CODEC_ID_ADPCM_G726LE,
+};
+#endif
+