AVPictureType enum misses the undefined type

[Martin Matuska]

In commit bebe72f4a05d338e04ae9ca1e9c6b72749b488aa, the enum AV_PICTURE_TYPE_* was introduced. There are still places in the code where pict_type is used as an integer and there is a case where "pict_type = 0" with the explanation "let ffmpeg decide what to do". The new enum does not know a value of 0 and C++ will fail if compiling such programs anyway as it is refered as an int (and you cannot patch them properly).

Examples:

ffmpeg.c:1290:                big_picture.pict_type = 0;  
libavfilter/libmpcodecs/vf_blackframe.c:89:    if (pict_type > 3 || pict_type < 0) pict_type = 0;

This is very important for git-oldabi but also relevant for git-master.

I suggest introducing a undefined type with a value of 0:

diff --git a/libavutil/avutil.h b/libavutil/avutil.h
index 33eacc7..a046d5b 100644
--- a/libavutil/avutil.h
+++ b/libavutil/avutil.h
@@ -104,7 +104,8 @@ enum AVMediaType {
 #define AV_TIME_BASE_Q          (AVRational){1, AV_TIME_BASE}
 
 enum AVPictureType {
-    AV_PICTURE_TYPE_I = 1, ///< Intra
+    AV_PICTURE_TYPE_NONE = 0 ///< Undefined
+    AV_PICTURE_TYPE_I,     ///< Intra
     AV_PICTURE_TYPE_P,     ///< Predicted
     AV_PICTURE_TYPE_B,     ///< Bi-dir predicted
     AV_PICTURE_TYPE_S,     ///< S(GMC)-VOP MPEG4

or fixing this problem in another way to preserve the compatibility with existing programs (oldabi).

[Stefano Sabatini]

The patch looks sane to me.

Michael?

[Michael Niedermayer]

yes, ill apply it in a moment

thx