[FFmpeg-devel] [PATCH]Write channel layout in aif files, v2

[Carl Eugen Hoyos]

Hi!

Attached allows to write the CHAN channel layout chunk to aif files.

Please comment, Carl Eugen
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diff --git a/libavformat/Makefile b/libavformat/Makefile
index 428c641..f1390fe 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -24,7 +24,7 @@ OBJS-$(CONFIG_AC3_MUXER)                 += rawenc.o
 OBJS-$(CONFIG_ADTS_MUXER)                += adtsenc.o
 OBJS-$(CONFIG_AEA_DEMUXER)               += aea.o pcm.o
 OBJS-$(CONFIG_AIFF_DEMUXER)              += aiffdec.o riff.o pcm.o isom.o
-OBJS-$(CONFIG_AIFF_MUXER)                += aiffenc.o riff.o
+OBJS-$(CONFIG_AIFF_MUXER)                += aiffenc.o riff.o isom.o
 OBJS-$(CONFIG_AMR_DEMUXER)               += amr.o
 OBJS-$(CONFIG_AMR_MUXER)                 += amr.o
 OBJS-$(CONFIG_ANM_DEMUXER)               += anm.o
diff --git a/libavformat/aiffenc.c b/libavformat/aiffenc.c
index cc3cbc4..8632e8c 100644
--- a/libavformat/aiffenc.c
+++ b/libavformat/aiffenc.c
@@ -22,6 +22,7 @@
 #include "avformat.h"
 #include "aiff.h"
 #include "avio_internal.h"
+#include "isom.h"
 
 typedef struct {
     int64_t form;
@@ -36,6 +37,7 @@ static int aiff_write_header(AVFormatContext *s)
     AVCodecContext *enc = s->streams[0]->codec;
     AVExtFloat sample_rate;
     int aifc = 0;
+    uint32_t layout_tag = ff_mov_get_chan(enc->channel_layout);
 
     /* First verify if format is ok */
     if (!enc->codec_tag)
@@ -61,6 +63,19 @@ static int aiff_write_header(AVFormatContext *s)
         avio_wb32(pb, 0xA2805140);
     }
 
+    if (enc->channels > 2 && layout_tag) {
+        ffio_wfourcc(pb, "CHAN");
+        avio_wb32(pb, 12);         //< mChunkSize
+        avio_wb32(pb, layout_tag); //< mChannelLayoutTag
+        avio_wb32(pb, 0);          //< mChannelBitmap
+        avio_wb32(pb, 0);          //< mNumberChannelDescriptions
+    } else if (enc->channels > 2 && enc->channel_layout) {
+        char name[32];
+        av_get_channel_layout_string(name, sizeof(name), enc->channels,
+                                     enc->channel_layout);
+        av_log(s, AV_LOG_WARNING, "Unsupported channel layout %s\n", name);
+    }
+
     /* Common chunk */
     ffio_wfourcc(pb, "COMM");
     avio_wb32(pb, aifc ? 24 : 18); /* size */
diff --git a/libavformat/isom.c b/libavformat/isom.c
index 76a7082..bb575f3 100644
--- a/libavformat/isom.c
+++ b/libavformat/isom.c
@@ -480,3 +480,11 @@ void ff_mov_read_chan(AVFormatContext *s, int64_t size, AVCodecContext *codec)
     avio_skip(pb, 8);
 }
 
+int32_t ff_mov_get_chan(uint64_t channel_layout) {
+    const MovChannelLayout *layouts;
+    for (layouts = mov_channel_layout; layouts->channel_layout; layouts++)
+        if (channel_layout == layouts->channel_layout)
+            return layouts->layout_tag;
+    return 0;
+}
+
diff --git a/libavformat/isom.h b/libavformat/isom.h
index 081d227..3090ab9 100644
--- a/libavformat/isom.h
+++ b/libavformat/isom.h
@@ -157,5 +157,6 @@ enum CodecID ff_mov_get_lpcm_codec_id(int bps, int flags);
 
 int ff_mov_read_stsd_entries(MOVContext *c, AVIOContext *pb, int entries);
 void ff_mov_read_chan(AVFormatContext *s, int64_t size, AVCodecContext *codec);
+int32_t ff_mov_get_chan(uint64_t channel_layout);
 
 #endif /* AVFORMAT_ISOM_H */