[FFmpeg-devel] [PATCH] avformat/aea: Add aea muxer

* [FFmpeg-devel] [PATCH] avformat/aea: Add aea muxer
@ 2024-03-08 11:19 asivery via ffmpeg-devel
  2024-03-08 11:22 ` Andreas Rheinhardt
  0 siblings, 1 reply; 15+ messages in thread
From: asivery via ffmpeg-devel @ 2024-03-08 11:19 UTC (permalink / raw)
  To: ffmpeg-devel; +Cc: asivery

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From 955fc035abbb5cfc1a52b1a5ea6900e4a21cef12 Mon Sep 17 00:00:00 2001
From: asivery <asivery@protonmail.com>
Date: Fri, 8 Mar 2024 11:17:51 +0100
Subject: [PATCH] avformat/aea: Add aea muxer

Signed-off-by: asivery <asivery@protonmail.com>
---
 libavformat/Makefile            |   3 +-
 libavformat/{aea.c => aeadec.c} |   0
 libavformat/aeaenc.c            | 134 ++++++++++++++++++++++++++++++++
 libavformat/allformats.c        |   1 +
 4 files changed, 137 insertions(+), 1 deletion(-)
 rename libavformat/{aea.c => aeadec.c} (100%)
 create mode 100644 libavformat/aeaenc.c

diff --git a/libavformat/Makefile b/libavformat/Makefile
index 4a380668bd..9855dcc707 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -91,7 +91,8 @@ OBJS-$(CONFIG_ADTS_MUXER)                += adtsenc.o apetag.o img2.o \
                                             id3v2enc.o
 OBJS-$(CONFIG_ADX_DEMUXER)               += adxdec.o
 OBJS-$(CONFIG_ADX_MUXER)                 += rawenc.o
-OBJS-$(CONFIG_AEA_DEMUXER)               += aea.o pcm.o
+OBJS-$(CONFIG_AEA_DEMUXER)               += aeadec.o pcm.o
+OBJS-$(CONFIG_AEA_MUXER)                 += aeaenc.o
 OBJS-$(CONFIG_AFC_DEMUXER)               += afc.o
 OBJS-$(CONFIG_AIFF_DEMUXER)              += aiffdec.o aiff.o pcm.o \
                                             mov_chan.o replaygain.o
diff --git a/libavformat/aea.c b/libavformat/aeadec.c
similarity index 100%
rename from libavformat/aea.c
rename to libavformat/aeadec.c
diff --git a/libavformat/aeaenc.c b/libavformat/aeaenc.c
new file mode 100644
index 0000000000..3ce4cec1ee
--- /dev/null
+++ b/libavformat/aeaenc.c
@@ -0,0 +1,134 @@
+/*
+ * MD STUDIO audio muxer
+ *
+ * Copyright (c) 2024 asivery
+ *
+ * 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 "libavutil/channel_layout.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/avstring.h"
+#include "avformat.h"
+#include "mux.h"
+
+typedef struct {
+    int block_count;
+} AeaMuxerContext;
+
+static int aea_init(AVFormatContext *s)
+{
+    AeaMuxerContext *c = s->priv_data;
+    c->block_count = 0;
+    
+    return 0;
+}
+
+static int aea_write_header(AVFormatContext *s)
+{
+    AVDictionaryEntry *title_entry;
+    int title_length = 0, i;
+    char* title_contents;
+    AVStream *st;
+
+
+    if (s->nb_streams > 1) {
+        av_log(s, AV_LOG_WARNING, "Got more than one stream to encode, they will be ignored.\n");
+    }
+    
+    st = s->streams[0];
+    if (st->codecpar->ch_layout.nb_channels != 1 && st->codecpar->ch_layout.nb_channels != 2) {
+        av_log(s, AV_LOG_ERROR, "Invalid amount of channels to mux (%d).\n", st->codecpar->ch_layout.nb_channels);
+        return AVERROR(EINVAL);
+    }
+
+    if (st->codecpar->sample_rate != 44100) {
+        av_log(s, AV_LOG_ERROR, "Invalid sample rate (%d) AEA only supports 44.1kHz.\n", st->codecpar->sample_rate);
+        return AVERROR(EINVAL);
+    }
+
+    /* Write magic */
+    avio_wl32(s->pb, 2048);
+    
+    /* Write AEA title */
+    title_entry = av_dict_get(st->metadata, "title", NULL, 0);
+    if (title_entry) {
+        title_contents = title_entry->value;
+        title_length = FFMIN(256, strlen(title_contents));
+    }
+
+    if (title_length) {
+        avio_write(s->pb, title_contents, title_length);
+    }
+
+    for (i = 0; i<(256 - title_length); i++) {
+        avio_w8(s->pb, 0);
+    }
+
+    /* Write number of frames (zero at header-writing time, will seek later), number of channels */
+    avio_wl32(s->pb, 0);
+    avio_w8(s->pb, st->codecpar->ch_layout.nb_channels);
+    avio_w8(s->pb, 0);
+
+    /* Write flags (meaning unknown) */ 
+    for(i = 0; i<11; i++) {
+        avio_wl32(s->pb, 0);
+    }
+
+    /* Pad the header to 2048 bytes */
+    for(i = 0; i<1738; i++) avio_w8(s->pb, 0);
+
+    return 0;
+}
+
+static int aea_write_packet(struct AVFormatContext *s, AVPacket *pkt)
+{
+    AeaMuxerContext *c = s->priv_data;
+    c->block_count++;
+
+    avio_write(s->pb, pkt->data, pkt->size);
+    return 0;
+}
+
+static int aea_write_trailer(struct AVFormatContext *s)
+{
+    AVIOContext *pb = s->pb;
+    AeaMuxerContext *c = s->priv_data;
+    if (pb->seekable & AVIO_SEEKABLE_NORMAL) {
+        /* Seek to rewrite the block count. */
+        avio_seek(pb, 260, SEEK_SET);
+        avio_wl32(pb, c->block_count * s->streams[0]->codecpar->ch_layout.nb_channels);
+    } else {
+        av_log(s, AV_LOG_WARNING, "unable to rewrite AEA header.\n");
+    }
+
+    return 0;
+}
+
+const FFOutputFormat ff_aea_muxer = {
+    .p.name           = "aea",
+    .p.long_name      = NULL_IF_CONFIG_SMALL("MD STUDIO audio"),
+    .priv_data_size   = sizeof(AeaMuxerContext),
+    .p.extensions     = "aea",
+    .p.audio_codec    = AV_CODEC_ID_ATRAC1,
+    .init             = aea_init,
+
+    .write_header     = aea_write_header,
+    .write_packet     = aea_write_packet,
+    .write_trailer    = aea_write_trailer,
+    .p.flags          = AVFMT_GENERIC_INDEX,
+};
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index b04b43cab3..1a50181447 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -46,6 +46,7 @@ extern const FFOutputFormat ff_adts_muxer;
 extern const AVInputFormat  ff_adx_demuxer;
 extern const FFOutputFormat ff_adx_muxer;
 extern const AVInputFormat  ff_aea_demuxer;
+extern const FFOutputFormat ff_aea_muxer;
 extern const AVInputFormat  ff_afc_demuxer;
 extern const AVInputFormat  ff_aiff_demuxer;
 extern const FFOutputFormat ff_aiff_muxer;
-- 
2.34.1


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