Compute ceil(log2(x)). * @param x value used to compute ceil(log2(x)) * @return computed ceiling of log2(x) */

* Clip a signed 64bit integer value into the amin-amax range. * @param a value to clip * @param amin minimum value of the clip range * @param amax

* Clip a signed integer value into the amin-amax range. * @param a value to clip * @param amin minimum value of the clip range * @param amax maximu

* Clip a signed integer value into the -32768,32767 range. * @param a value to clip * @return clipped value */

* Clip a signed integer value into the -128,127 range. * @param a value to clip * @return clipped value */

* Clip a signed integer into the -(2^p),(2^p-1) range. * @param a value to clip * @param p bit position to clip at * @return clipped value */

* Clip a signed integer value into the 0-65535 range. * @param a value to clip * @return clipped value */

* Clip a signed integer value into the 0-255 range. * @param a value to clip * @return clipped value */

* Clip a signed integer to an unsigned power of two range. * @param a value to clip * @param p bit position to clip at * @return clipped value *

* Clip a double value into the amin-amax range. * @param a value to clip * @param amin minimum value of the clip range * @param amax maximum value

* Clip a float value into the amin-amax range. * @param a value to clip * @param amin minimum value of the clip range * @param amax maximum value o

* Clip a signed 64-bit integer value into the -2147483648,2147483647 range. * @param a value to clip * @return clipped value */

* Compare two rationals. * * @param a First rational * @param b Second rational * * @return One of the following values: * - 0 if `a ==

* Reinterpret a double as a 64-bit integer. */

* Return a pointer to the data stored in a FIFO buffer at a certain offset. * The FIFO buffer is not modified. * * @param f AVFifoBuffer to peek

* Reinterpret a float as a 32-bit integer. */

* Reinterpret a 64-bit integer as a double. */

* Reinterpret a 32-bit integer as a float. */

* Locale-independent conversion of ASCII isgraph. */

* Locale-independent conversion of ASCII isspace. */

* Locale-independent conversion of ASCII isxdigit. */

* Get the next random unsigned 32-bit number using an ALFG. * * Please also consider a simple LCG like state= state*1664525+1013904223, * it may be

* Fill the provided buffer with a string containing an error string * corresponding to the AVERROR code errnum. * * @param errbuf a buffer

* Create an AVRational. * * Useful for compilers that do not support compound literals. * * @note The return value is not reduced. * @see av_redu

* Get the next random unsigned 32-bit number using a MLFG. * * Please also consider av_lfg_get() above, it is faster. */

* Clear high bits from an unsigned integer starting with specific bit position * @param a value to clip * @param p bit position to clip at * @ret

* Count number of bits set to one in x * @param x value to count bits of * @return the number of bits set to one in x */

* Count number of bits set to one in x * @param x value to count bits of * @return the number of bits set to one in x */

* Add two signed 32-bit values with saturation. * * @param a one value * @param b another value * @return sum with signed saturation */

* Add a doubled value to another value with saturation at both stages. * * @param a first value * @param b value doubled and added to a * @retur

* Subtract a doubled value from another value with saturation at both stages. * * @param a first value * @param b value doubled and subtracted fr

* Subtract two signed 32-bit values with saturation. * * @param a one value * @param b another value * @return difference with signed saturation

* Multiply two `size_t` values checking for overflow. * * @param[in] a,b Operands of multiplication * @param[out] r Pointer to the result of the

* Get the count of continuous non zero chars starting from the beginning. * * @param len maximum number of characters to check in the string, that

* Locale-independent conversion of ASCII characters to uppercase. */

* Fill the provided buffer with a string containing a timestamp * representation. * * @param buf a buffer with size in bytes of at least AV_TS_MAX_

* Fill the provided buffer with a string containing a timestamp time * representation. * * @param buf a buffer with size in bytes of at least AV_TS

* Return x default pointer in case p is NULL. */

* ftell() equivalent for AVIOContext. * @return position or AVERROR. */

* 解码器上下文 * @return */

* 配置默认显示的窗口 */

* 配置FBO窗口 */