+#define AV_PERM_READ 0x01 ///< can read from the buffer
+#define AV_PERM_WRITE 0x02 ///< can write to the buffer
+#define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
+#define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
+#define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
+#define AV_PERM_NEG_LINESIZES 0x20 ///< the buffer requested can have negative linesizes
+
+/**
+ * Audio specific properties in a reference to an AVFilterBuffer. Since
+ * AVFilterBufferRef is common to different media formats, audio specific
+ * per reference properties must be separated out.
+ */
+typedef struct AVFilterBufferRefAudioProps {
+ int64_t channel_layout; ///< channel layout of audio buffer
+ int nb_samples; ///< number of audio samples
+ int size; ///< audio buffer size
+ uint32_t sample_rate; ///< audio buffer sample rate
+ int planar; ///< audio buffer - planar or packed
+} AVFilterBufferRefAudioProps;
+
+/**
+ * Video specific properties in a reference to an AVFilterBuffer. Since
+ * AVFilterBufferRef is common to different media formats, video specific
+ * per reference properties must be separated out.
+ */
+typedef struct AVFilterBufferRefVideoProps {
+ int w; ///< image width
+ int h; ///< image height
+ AVRational pixel_aspect; ///< pixel aspect ratio
+ int interlaced; ///< is frame interlaced
+ int top_field_first; ///< field order
+} AVFilterBufferRefVideoProps;
+