lavf: deprecate avformat_alloc_output_context() in favor of avformat_alloc_output_context2()

The new function accepts a slightly more intuitive order of paramters,
and returns an error code, thus allowing applications to report a
meaningful error message.

1 files changed, 22 insertions, 3 deletions

diff --git a/libavformat/utils.c b/libavformat/utils.c
index c5e570028e..71c325a542 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -2751,8 +2751,13 @@ int av_set_parameters(AVFormatContext *s, AVFormatParameters *ap)
     return 0;
 }
 
-AVFormatContext *avformat_alloc_output_context(const char *format, AVOutputFormat *oformat, const char *filename){
+int avformat_alloc_output_context2(AVFormatContext **avctx, AVOutputFormat *oformat,
+                                   const char *format, const char *filename)
+{
     AVFormatContext *s= avformat_alloc_context();
+    int ret = 0;
+
+    *avctx = NULL;
     if(!s)
         goto nomem;
 
@@ -2761,11 +2766,13 @@ AVFormatContext *avformat_alloc_output_context(const char *format, AVOutputForma
             oformat = av_guess_format(format, NULL, NULL);
             if (!oformat) {
                 av_log(s, AV_LOG_ERROR, "Requested output format '%s' is not a suitable output format\n", format);
+                ret = AVERROR(EINVAL);
                 goto error;
             }
         } else {
             oformat = av_guess_format(NULL, filename, NULL);
             if (!oformat) {
+                ret = AVERROR(EINVAL);
                 av_log(s, AV_LOG_ERROR, "Unable to find a suitable output format for '%s'\n",
                         filename);
                 goto error;
@@ -2787,14 +2794,26 @@ AVFormatContext *avformat_alloc_output_context(const char *format, AVOutputForma
 
     if(filename)
         av_strlcpy(s->filename, filename, sizeof(s->filename));
-    return s;
+    *avctx = s;
+    return 0;
 nomem:
     av_log(s, AV_LOG_ERROR, "Out of memory\n");
+    ret = AVERROR(ENOMEM);
 error:
     avformat_free_context(s);
-    return NULL;
+    return ret;
 }
 
+#if FF_API_ALLOC_OUTPUT_CONTEXT
+AVFormatContext *avformat_alloc_output_context(const char *format,
+                                               AVOutputFormat *oformat, const char *filename)
+{
+    AVFormatContext *avctx;
+    int ret = avformat_alloc_output_context2(&avctx, oformat, format, filename);
+    return ret < 0 ? NULL : avctx;
+}
+#endif
+
 static int validate_codec_tag(AVFormatContext *s, AVStream *st)
 {
     const AVCodecTag *avctag;