From 3e79c2adb16e4085ffdcac6055ef8379b70224c4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Storsj=C3=B6?= <martin@martin.st>
Date: Fri, 16 Dec 2011 12:48:09 +0200
Subject: [PATCH] libavformat: Add a utility function for adding parameter
 change side data
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Signed-off-by: Martin Storsjö <martin@martin.st>
---
 libavformat/internal.h |  8 ++++++++
 libavformat/utils.c    | 43 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/libavformat/internal.h b/libavformat/internal.h
index 45736687d3d..559e710014d 100644
--- a/libavformat/internal.h
+++ b/libavformat/internal.h
@@ -299,4 +299,12 @@ int64_t ff_gen_search(AVFormatContext *s, int stream_index,
 void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits,
                          unsigned int pts_num, unsigned int pts_den);
 
+/**
+ * Add side data to a packet for changing parameters to the given values.
+ * Parameters set to 0 aren't included in the change.
+ */
+int ff_add_param_change(AVPacket *pkt, int32_t channels,
+                        uint64_t channel_layout, int32_t sample_rate,
+                        int32_t width, int32_t height);
+
 #endif /* AVFORMAT_INTERNAL_H */
diff --git a/libavformat/utils.c b/libavformat/utils.c
index bc5b7e02da1..aa2c276b909 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -25,6 +25,7 @@
 #include "avio_internal.h"
 #include "internal.h"
 #include "libavcodec/internal.h"
+#include "libavcodec/bytestream.h"
 #include "libavutil/opt.h"
 #include "libavutil/dict.h"
 #include "libavutil/pixdesc.h"
@@ -4017,3 +4018,45 @@ int avformat_network_deinit(void)
 #endif
     return 0;
 }
+
+int ff_add_param_change(AVPacket *pkt, int32_t channels,
+                        uint64_t channel_layout, int32_t sample_rate,
+                        int32_t width, int32_t height)
+{
+    uint32_t flags = 0;
+    int size = 4;
+    uint8_t *data;
+    if (!pkt)
+        return AVERROR(EINVAL);
+    if (channels) {
+        size += 4;
+        flags |= AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_COUNT;
+    }
+    if (channel_layout) {
+        size += 8;
+        flags |= AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_LAYOUT;
+    }
+    if (sample_rate) {
+        size += 4;
+        flags |= AV_SIDE_DATA_PARAM_CHANGE_SAMPLE_RATE;
+    }
+    if (width || height) {
+        size += 8;
+        flags |= AV_SIDE_DATA_PARAM_CHANGE_DIMENSIONS;
+    }
+    data = av_packet_new_side_data(pkt, AV_PKT_DATA_PARAM_CHANGE, size);
+    if (!data)
+        return AVERROR(ENOMEM);
+    bytestream_put_le32(&data, flags);
+    if (channels)
+        bytestream_put_le32(&data, channels);
+    if (channel_layout)
+        bytestream_put_le64(&data, channel_layout);
+    if (sample_rate)
+        bytestream_put_le32(&data, sample_rate);
+    if (width || height) {
+        bytestream_put_le32(&data, width);
+        bytestream_put_le32(&data, height);
+    }
+    return 0;
+}
-- 
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