* simultaneously. And BRC would adjust accordingly. This is so called
* Parallel BRC. */
#define VA_RC_PARALLEL 0x00000200
+/** \brief Quality defined VBR
+ * Use Quality factor to determine the good enough QP for each MB such that
+ * good enough quality can be obtained without waste of bits
+ * for this BRC mode, you must set all legacy VBR parameters
+ * and reuse quality_factor in \c VAEncMiscParameterRateControl
+ * */
+#define VA_RC_QVBR 0x00000400
/**@}*/
/** \brief Rate control parameters */
typedef struct _VAEncMiscParameterRateControl
{
- /* this is the maximum bit-rate to be constrained by the rate control implementation */
+ /** The maximum bit-rate which the the rate controller should generate. */
uint32_t bits_per_second;
- /* this is the bit-rate the rate control is targeting, as a percentage of the maximum
- * bit-rate for example if target_percentage is 95 then the rate control will target
- * a bit-rate that is 95% of the maximum bit-rate
+ /** The target bit-rate which the rate controller should generate, as a percentage of the
+ * maximum bit-rate.
+ *
+ * In CBR mode this value is ignored (treated as 100%).
*/
uint32_t target_percentage;
- /* windows size in milliseconds. For example if this is set to 500,
- * then the rate control will guarantee the target bit-rate over a 500 ms window
+ /** Rate control window size in milliseconds.
+ *
+ * The rate controller will attempt to guarantee that the target and maximum bit-rates are
+ * correct over this window.
*/
uint32_t window_size;
- /* initial QP at I frames */
+ /** Initial quantiser value used at the start of the stream.
+ *
+ * Ignored if set to zero.
+ */
uint32_t initial_qp;
+ /** Minimum quantiser value to use.
+ *
+ * The quantiser will not go below the value - if this limit is hit, the output bitrate may
+ * be lower than the target. Ignored if set to zero.
+ */
uint32_t min_qp;
+ /** Basic unit size.
+ *
+ * Only used by some drivers - see driver documentation for details. Set to zero if unused.
+ */
uint32_t basic_unit_size;
union
{
struct
{
+ /** Force rate controller reset.
+ *
+ * The next frame will be treated as the start of a new stream, with all rate
+ * controller state reset to its initial values.
+ */
uint32_t reset : 1;
- uint32_t disable_frame_skip : 1; /* Disable frame skip in rate control mode */
- uint32_t disable_bit_stuffing : 1; /* Disable bit stuffing in rate control mode */
- uint32_t mb_rate_control : 4; /* Control VA_RC_MB 0: default, 1: enable, 2: disable, other: reserved*/
- /*
- * The temporal layer that the rate control parameters are specified for.
+ /** Disable frame skip in rate control mode. */
+ uint32_t disable_frame_skip : 1;
+ /** Disable bit stuffing in rate control mode. */
+ uint32_t disable_bit_stuffing : 1;
+ /** Macroblock-level rate control.
+ *
+ * 0: use default, 1: always enable, 2: always disable, other: reserved.
+ *
+ * This feature is only available if VAConfigAttribRateControl has the
+ * \ref VA_RC_MB bit set.
*/
+ uint32_t mb_rate_control : 4;
+ /** The temporal layer that these rate control parameters apply to. */
uint32_t temporal_id : 8;
- uint32_t cfs_I_frames : 1; /* I frame also follows CFS */
+ /** Ensure that intra frames also conform to the constant frame size. */
+ uint32_t cfs_I_frames : 1;
+ /** Enable parallel rate control for hierarchical B frames.
+ *
+ * See \ref VA_RC_PARALLEL.
+ */
uint32_t enable_parallel_brc : 1;
uint32_t enable_dynamic_scaling : 1;
- /** \brief Frame Tolerance Mode
+ /** Frame tolerance mode.
+ *
* Indicates the tolerance the application has to variations in the frame size.
* For example, wireless display scenarios may require very steady bit rate to
* reduce buffering time. It affects the rate control algorithm used,
* other -- invalid.
*/
uint32_t frame_tolerance_mode : 2;
+ /** Reserved for future use, must be zero. */
uint32_t reserved : 12;
} bits;
uint32_t value;
} rc_flags;
- uint32_t ICQ_quality_factor; /* Initial ICQ quality factor: 1-51. */
- /** \brief Reserved bytes for future use, must be zero */
+ /** Initial quality factor used in ICQ mode.
+ *
+ * This value must be between 1 and 51.
+ * this value will be deprecated in future, to use quality_factor instead of it.
+ */
+ uint32_t ICQ_quality_factor;
+ /** Maximum quantiser value to use.
+ *
+ * The quantiser will not go above this value - if this limit is hit, the output bitrate
+ * may exceed the target. Ignored if set to zero.
+ */
uint32_t max_qp;
- uint32_t va_reserved[VA_PADDING_MEDIUM - 2];
+ /** Quality factor
+ *
+ * the range will be different for different codec
+ */
+ uint32_t quality_factor;
+ /** Reserved bytes for future use, must be zero. */
+ uint32_t va_reserved[VA_PADDING_MEDIUM - 3];
} VAEncMiscParameterRateControl;
+/** Encode framerate parameters.
+ *
+ * Sets the encode framerate used by the rate controller. This should be
+ * provided in all modes using a bitrate target (variable framerate is not
+ * supported).
+ */
typedef struct _VAEncMiscParameterFrameRate
{
- /*
+ /** Encode framerate.
+ *
* The framerate is specified as a number of frames per second, as a
* fraction. The denominator of the fraction is given in the top half
* (the high two bytes) of the framerate field, and the numerator is
{
struct
{
- /*
- * The temporal id the framerate parameters are specified for.
- */
+ /** The temporal layer that these framerate parameters apply to. */
uint32_t temporal_id : 8;
+ /** Reserved for future use, must be zero. */
uint32_t reserved : 24;
} bits;
uint32_t value;
uint32_t va_reserved[VA_PADDING_LOW];
} VAEncMiscParameterRIR;
+/** HRD / VBV buffering parameters for encoding.
+ *
+ * This sets the HRD / VBV parameters which will be used by the rate
+ * controller for encoding. It should be specified in modes using a bitrate
+ * target when the buffering of the output stream needs to be constrained.
+ *
+ * If not provided, the encoder may use arbitrary amounts of buffering.
+ */
typedef struct _VAEncMiscParameterHRD
{
- uint32_t initial_buffer_fullness; /* in bits */
- uint32_t buffer_size; /* in bits */
+ /** The initial fullness of the HRD coded picture buffer, in bits.
+ *
+ * This sets how full the CPB is when encoding begins - that is, how much
+ * buffering will happen on the decoder side before the first frame.
+ * The CPB fullness will be reset to this value after any rate control
+ * reset (a change in parameters or an explicit reset).
+ *
+ * For H.264, it should match the value of initial_cpb_removal_delay in
+ * buffering_period SEI messages.
+ */
+ uint32_t initial_buffer_fullness;
+ /** The HRD coded picture buffer size, in bits.
+ *
+ * For H.264, it should match the value of cpb_size_value_minus1 in the VUI
+ * parameters.
+ */
+ uint32_t buffer_size;
/** \brief Reserved bytes for future use, must be zero */
uint32_t va_reserved[VA_PADDING_LOW];
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