avcodec/avpacket: add av_packet_make_writable()

Useful as well to quickly make a packet reference counted when it
isn't already so.

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

1 files changed, 24 insertions, 0 deletions

diff --git a/libavcodec/avpacket.c b/libavcodec/avpacket.c
index fe8113ab76..0693ca6f62 100644
--- a/libavcodec/avpacket.c
+++ b/libavcodec/avpacket.c
@@ -652,6 +652,30 @@ void av_packet_move_ref(AVPacket *dst, AVPacket *src)
     src->size = 0;
 }
 
+int av_packet_make_writable(AVPacket *pkt)
+{
+    AVBufferRef *buf = NULL;
+    int ret;
+
+    if (pkt->buf && av_buffer_is_writable(pkt->buf))
+        return 0;
+
+    if (!pkt->data)
+        return AVERROR(EINVAL);
+
+    ret = packet_alloc(&buf, pkt->size);
+    if (ret < 0)
+        return ret;
+    if (pkt->size)
+        memcpy(buf->data, pkt->data, pkt->size);
+
+    av_buffer_unref(&pkt->buf);
+    pkt->buf  = buf;
+    pkt->data = buf->data;
+
+    return 0;
+}
+
 void av_packet_rescale_ts(AVPacket *pkt, AVRational src_tb, AVRational dst_tb)
 {
     if (pkt->pts != AV_NOPTS_VALUE)