1 files changed, 30 insertions, 0 deletions
diff --git a/libavutil/crc.h b/libavutil/crc.h
index 5c25607bbc..142a5b5e8f 100644
--- a/libavutil/crc.h
+++ b/libavutil/crc.h
@@ -36,8 +36,38 @@ typedef enum {
     AV_CRC_MAX,         /*< Not part of public API! Do not use outside libavutil. */
 }AVCRCId;
 
+/**
+ * Initialize a CRC table.
+ * @param ctx must be an array of size sizeof(AVCRC)*257 or sizeof(AVCRC)*1024
+ * @param le If 1, the lowest bit represents the coefficient for the highest
+ *           exponent of the corresponding polynomial (both for poly and
+ *           actual CRC).
+ *           If 0, you must swap the CRC parameter and the result of av_crc
+ *           if you need the standard representation (can be simplified in
+ *           most cases to e.g. bswap16):
+ *           av_bswap32(crc << (32-bits))
+ * @param bits number of bits for the CRC
+ * @param poly generator polynomial without the x**bits coefficient, in the
+ *             representation as specified by le
+ * @param ctx_size size of ctx in bytes
+ * @return <0 on failure
+ */
 int av_crc_init(AVCRC *ctx, int le, int bits, uint32_t poly, int ctx_size);
+
+/**
+ * Get an initialized standard CRC table.
+ * @param crc_id ID of a standard CRC
+ * @return a pointer to the CRC table or NULL on failure
+ */
 const AVCRC *av_crc_get_table(AVCRCId crc_id);
+
+/**
+ * Calculate the CRC of a block.
+ * @param crc CRC of previous blocks if any or initial value for CRC
+ * @return CRC updated with the data from the given block
+ *
+ * @see av_crc_init() "le" parameter
+ */
 uint32_t av_crc(const AVCRC *ctx, uint32_t start_crc, const uint8_t *buffer, size_t length) av_pure;
 
 #endif /* AVUTIL_CRC_H */