AST Muxer

Signed-off-by: James Almer <jamrial@gmail.com>

1 files changed, 202 insertions, 0 deletions

diff --git a/libavformat/astenc.c b/libavformat/astenc.c
new file mode 100644
index 0000000000..2c4afb7afb
--- /dev/null
+++ b/libavformat/astenc.c
@@ -0,0 +1,202 @@
+/*
+ * AST muxer
+ * Copyright (c) 2012 James Almer
+ *
+ * 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 "avio_internal.h"
+#include "internal.h"
+#include "ast.h"
+#include "libavutil/mathematics.h"
+#include "libavutil/opt.h"
+
+typedef struct ASTMuxContext {
+    AVClass *class;
+    int64_t  size;
+    int64_t  samples;
+    int64_t  loopstart;
+    int64_t  loopend;
+    int      fbs;
+} ASTMuxContext;
+
+#define CHECK_LOOP(type) \
+    if (ast->loop ## type) { \
+        ast->loop ## type = av_rescale_q_rnd(ast->loop ## type, (AVRational){enc->sample_rate, 1}, (AVRational){1000, 1}, AV_ROUND_DOWN); \
+        if (ast->loop ## type < 0 || ast->loop ## type > UINT_MAX) { \
+            av_log(s, AV_LOG_ERROR, "Invalid loop" #type " value\n"); \
+            return AVERROR(EINVAL);  \
+        } \
+    }
+
+static int ast_write_header(AVFormatContext *s)
+{
+    ASTMuxContext *ast = s->priv_data;
+    AVIOContext *pb = s->pb;
+    AVCodecContext *enc;
+    unsigned int codec_tag;
+
+    if (s->nb_streams = 1) {
+        enc = s->streams[0]->codec;
+    } else {
+        av_log(s, AV_LOG_ERROR, "only one stream is supported\n");
+        return AVERROR(EINVAL);
+    }
+
+    if (enc->codec_id == AV_CODEC_ID_ADPCM_AFC) {
+        av_log(s, AV_LOG_ERROR, "muxing ADPCM AFC is not implemented\n");
+        return AVERROR_PATCHWELCOME;
+    }
+
+    codec_tag = ff_codec_get_tag(ff_codec_ast_tags, enc->codec_id);
+    if (!codec_tag) {
+        av_log(s, AV_LOG_ERROR, "unsupported codec\n");
+        return AVERROR(EINVAL);
+    }
+
+    if (ast->loopstart && ast->loopend && ast->loopstart >= ast->loopend) {
+        av_log(s, AV_LOG_ERROR, "loopend can't be less or equal to loopstart\n");
+        return AVERROR(EINVAL);
+    }
+
+    /* Convert milliseconds to samples */
+    CHECK_LOOP(start)
+    CHECK_LOOP(end)
+
+    ffio_wfourcc(pb, "STRM");
+
+    ast->size = avio_tell(pb);
+    avio_wb32(pb, 0); /* File size minus header */
+    avio_wb16(pb, codec_tag);
+    avio_wb16(pb, 16); /* Bit depth */
+    avio_wb16(pb, enc->channels);
+    avio_wb16(pb, 0xFFFF);
+    avio_wb32(pb, enc->sample_rate);
+
+    ast->samples = avio_tell(pb);
+    avio_wb32(pb, 0); /* Number of samples */
+    avio_wb32(pb, 0); /* Loopstart */
+    avio_wb32(pb, 0); /* Loopend */
+    avio_wb32(pb, 0); /* Size of first block */
+
+    /* Unknown */
+    avio_wb32(pb, 0);
+    avio_wl32(pb, 0x7F);
+    avio_wb64(pb, 0);
+    avio_wb64(pb, 0);
+    avio_wb32(pb, 0);
+
+    avio_flush(pb);
+
+    return 0;
+}
+
+static int ast_write_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    AVIOContext *pb = s->pb;
+    ASTMuxContext *ast = s->priv_data;
+    AVCodecContext *enc = s->streams[0]->codec;
+    int size = pkt->size / enc->channels;
+
+    if (enc->frame_number == 1)
+        ast->fbs = size;
+
+    ffio_wfourcc(pb, "BLCK");
+    avio_wb32(pb, size); /* Block size */
+
+    /* padding */
+    avio_wb64(pb, 0);
+    avio_wb64(pb, 0);
+    avio_wb64(pb, 0);
+
+    avio_write(pb, pkt->data, pkt->size);
+
+    return 0;
+}
+
+static int ast_write_trailer(AVFormatContext *s)
+{
+    AVIOContext *pb = s->pb;
+    ASTMuxContext *ast = s->priv_data;
+    AVCodecContext *enc = s->streams[0]->codec;
+    int64_t file_size = avio_tell(pb);
+    int64_t samples = (file_size - 64 - (32 * enc->frame_number)) / enc->block_align; /* PCM_S16BE_PLANAR */
+
+    av_log(s, AV_LOG_DEBUG, "total samples: %"PRId64"\n", samples);
+
+    if (s->pb->seekable) {
+        /* File size minus header */
+        avio_seek(pb, ast->size, SEEK_SET);
+        avio_wb32(pb, file_size - 64);
+
+        /* Number of samples */
+        avio_seek(pb, ast->samples, SEEK_SET);
+        avio_wb32(pb, samples);
+
+        /* Loopstart if provided */
+        if (ast->loopstart && ast->loopstart >= samples) {
+            av_log(s, AV_LOG_WARNING, "Loopstart value is out of range and will be ignored\n");
+            ast->loopstart = 0;
+        }
+        avio_wb32(pb, ast->loopstart);
+
+        /* Loopend if provided. Otherwise number of samples again */
+        if (ast->loopend) {
+            if (ast->loopend > samples) {
+                av_log(s, AV_LOG_WARNING, "Loopend value is out of range and will be ignored\n");
+                ast->loopend = samples;
+            }
+            avio_wb32(pb, ast->loopend);
+        } else {
+            avio_wb32(pb, samples);
+        }
+
+        /* Size of first block */
+        avio_wb32(pb, ast->fbs);
+        avio_flush(pb);
+    }
+    return 0;
+}
+
+#define OFFSET(obj) offsetof(ASTMuxContext, obj)
+static const AVOption options[] = {
+  { "loopstart", "Loopstart position in milliseconds.", OFFSET(loopstart), AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
+  { "loopend",   "Loopend position in milliseconds.",   OFFSET(loopend),   AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
+  { NULL },
+};
+
+static const AVClass ast_muxer_class = {
+    .class_name = "AST muxer",
+    .item_name  = av_default_item_name,
+    .option     = options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+AVOutputFormat ff_ast_muxer = {
+    .name              = "ast",
+    .long_name         = NULL_IF_CONFIG_SMALL("AST (Audio Stream)"),
+    .extensions        = "ast",
+    .priv_data_size    = sizeof(ASTMuxContext),
+    .audio_codec       = AV_CODEC_ID_PCM_S16BE_PLANAR,
+    .video_codec       = AV_CODEC_ID_NONE,
+    .write_header      = ast_write_header,
+    .write_packet      = ast_write_packet,
+    .write_trailer     = ast_write_trailer,
+    .priv_class        = &ast_muxer_class,
+    .codec_tag         = (const AVCodecTag* const []){ff_codec_ast_tags, 0},
+};