encoder/irc_est_sad.c

/******************************************************************************
 *
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 *****************************************************************************
 * Originally developed and contributed by Ittiam Systems Pvt. Ltd, Bangalore
*/

/*****************************************************************************/
/* Includes */
/*****************************************************************************/

/* User include files */
#include "irc_datatypes.h"
#include "irc_cntrl_param.h"
#include "irc_mem_req_and_acq.h"
#include "irc_est_sad.h"
#include "irc_common.h"

typedef struct est_sad_t
{
    WORD32 i4_use_est_intra_sad;

    /* Previous frame SAD */
    UWORD32 au4_prev_frm_sad[MAX_PIC_TYPE];

    /* Current (nth) ifi average P frame SAD */
    UWORD32 u4_n_p_frm_ifi_avg_sad;

    /* (n-1)th ifi average P frame SAD */
    UWORD32 u4_n_1_p_frm_ifi_avg_sad;

    /* (n-2)th ifi average P frame SAD */
    UWORD32 u4_n_2_p_frm_ifi_avg_sad;

    /* number of ifi encoded till now */
    WORD32 i4_num_ifi_encoded;

    /* number of P frames in the current IFI */
    WORD32 i4_num_p_frm_in_cur_ifi;

} est_sad_t;

WORD32 irc_est_sad_num_fill_use_free_memtab(est_sad_t **pps_est_sad,
                                            itt_memtab_t *ps_memtab,
                                            ITT_FUNC_TYPE_E e_func_type)
{
    WORD32 i4_mem_tab_idx = 0;
    est_sad_t s_est_sad;

    /* Hack for al alloc, during which we don't have any state memory.
     * Dereferencing can cause issues
     */
    if(e_func_type == GET_NUM_MEMTAB || e_func_type == FILL_MEMTAB)
        (*pps_est_sad) = &s_est_sad;

    /* For src rate control state structure */
    if(e_func_type != GET_NUM_MEMTAB)
    {
        fill_memtab(&ps_memtab[i4_mem_tab_idx], sizeof(est_sad_t),
                    ALIGN_128_BYTE, PERSISTENT, DDR);
        use_or_fill_base(&ps_memtab[0], (void**)pps_est_sad, e_func_type);
    }
    i4_mem_tab_idx++;

    return (i4_mem_tab_idx);
}

void irc_init_est_sad(est_sad_t *ps_est_sad, WORD32 i4_use_est_intra_sad)
{
    WORD32 i;
    ps_est_sad->i4_use_est_intra_sad = i4_use_est_intra_sad;

    for(i = 0; i < MAX_PIC_TYPE; i++)
    {
        ps_est_sad->au4_prev_frm_sad[i] = 0;
    }

    ps_est_sad->u4_n_p_frm_ifi_avg_sad = 0;
    ps_est_sad->u4_n_1_p_frm_ifi_avg_sad = 0;
    ps_est_sad->u4_n_2_p_frm_ifi_avg_sad = 0;
    ps_est_sad->i4_num_ifi_encoded = 0;
    ps_est_sad->i4_num_p_frm_in_cur_ifi = 0;
}

void irc_reset_est_sad(est_sad_t *ps_est_sad)
{
    irc_init_est_sad(ps_est_sad, ps_est_sad->i4_use_est_intra_sad);
}

/*
 * Get estimated SAD can be called at any point. The various use cases are:
 * 1) When a I frame is getting encoded,
 *    - get the estimated of P => No issues since we use the last coded P frame
 *      value
 *    - get estimated of I => This call for two cases:
 *    => a) if num_ifi_encoded is less than 2
 *          then return the previous encoded I frame sad
 *    => b) if num_ifi_encoded is more than 2, then we scale
 *          the prev I sad by the ratio of (n-1) ifi P to n-2 ifi P
 * 2) When P frame is getting encoded,
 *    - get the estimated of P =>  No issues since we use the last coded P frame value
 *    - get the estimated of I => Simillar to I we have two cases.
 *      To handle the b) case extra logic had to introduced using
 *      u1_is_n_1_p_frm_ifi_avg_sad_usable flag
 */
UWORD32 irc_get_est_sad(est_sad_t *ps_est_sad, picture_type_e e_pic_type)
{
    if(ps_est_sad->i4_use_est_intra_sad)
    {
        UWORD32 u4_estimated_sad;
        if(e_pic_type == P_PIC)
        {
            u4_estimated_sad = ps_est_sad->au4_prev_frm_sad[P_PIC];
        }
        else if(e_pic_type == B_PIC)
        {
            u4_estimated_sad = ps_est_sad->au4_prev_frm_sad[B_PIC];
        }
        else
        {
            if(ps_est_sad->i4_num_ifi_encoded < 2)
            {
                /*
                 * Only one IFI has been encoded and so use the previous I
                 * frames SAD
                 */
                u4_estimated_sad = ps_est_sad->au4_prev_frm_sad[I_PIC];
            }
            else
            {
                /*
                 * Since the n-1 'P' frame IFI would have just accumulated the
                 * frame sads we average it out here
                 */
                UWORD32 u4_n_1_p_frm_ifi_avg_sad, u4_n_2_p_frm_ifi_avg_sad;
                number_t vq_n_1_p_frm_ifi_avg_sad, vq_n_2_p_frm_ifi_avg_sad;
                number_t vq_prev_frm_sad_i;

                /*
                 * If there are frames in the current IFI start using it to
                 * estimate the I frame SAD
                 */
                if(ps_est_sad->i4_num_p_frm_in_cur_ifi)
                {
                    u4_n_1_p_frm_ifi_avg_sad =
                                    (ps_est_sad->u4_n_p_frm_ifi_avg_sad
                                     / ps_est_sad->i4_num_p_frm_in_cur_ifi);
                    u4_n_2_p_frm_ifi_avg_sad =
                                    ps_est_sad->u4_n_1_p_frm_ifi_avg_sad;
                }
                else
                {
                    u4_n_1_p_frm_ifi_avg_sad =
                                    ps_est_sad->u4_n_1_p_frm_ifi_avg_sad;
                    u4_n_2_p_frm_ifi_avg_sad =
                                    ps_est_sad->u4_n_2_p_frm_ifi_avg_sad;
                }

                /*
                 * If any of the previous p frame SADs are zeros we just return
                 * the previous I frame SAD
                 */
                if(u4_n_1_p_frm_ifi_avg_sad && u4_n_2_p_frm_ifi_avg_sad)
                {
                    SET_VAR_Q(vq_prev_frm_sad_i,
                              ps_est_sad->au4_prev_frm_sad[I_PIC], 0);
                    SET_VAR_Q(vq_n_1_p_frm_ifi_avg_sad,
                              u4_n_1_p_frm_ifi_avg_sad, 0);
                    SET_VAR_Q(vq_n_2_p_frm_ifi_avg_sad,
                              u4_n_2_p_frm_ifi_avg_sad, 0);
                    /*
                     * Estimated SAD =
                     *(n-1)th intra frame interval(ifi) P frame Avg SAD *
                     *(prev I frame SAD /
                     *(prev (n-2)nd intra frame interval(ifi) P frame Avg SAD)
                     */
                    mult32_var_q(vq_prev_frm_sad_i, vq_n_1_p_frm_ifi_avg_sad,
                                 &vq_prev_frm_sad_i);
                    div32_var_q(vq_prev_frm_sad_i, vq_n_2_p_frm_ifi_avg_sad,
                                &vq_prev_frm_sad_i);
                    number_t_to_word32(vq_prev_frm_sad_i,
                                       (WORD32*)&u4_estimated_sad);
                }
                else
                {
                    u4_estimated_sad = ps_est_sad->au4_prev_frm_sad[I_PIC];
                }
            }
        }
        return u4_estimated_sad;
    }
    else
    {
        return ps_est_sad->au4_prev_frm_sad[e_pic_type];
    }
}

void irc_update_actual_sad(est_sad_t *ps_est_sad,
                           UWORD32 u4_actual_sad,
                           picture_type_e e_pic_type)
{
    ps_est_sad->au4_prev_frm_sad[e_pic_type] = u4_actual_sad;

    if(ps_est_sad->i4_use_est_intra_sad)
    {
        if(e_pic_type == I_PIC)
        {
            /* The requirement is to have two IFI before estimating I frame SAD */
            if(ps_est_sad->i4_num_ifi_encoded < 2)
                ps_est_sad->i4_num_ifi_encoded++;

            /* Calculate the average SAD */
            if(ps_est_sad->i4_num_p_frm_in_cur_ifi)
            {
                ps_est_sad->u4_n_p_frm_ifi_avg_sad /=
                                ps_est_sad->i4_num_p_frm_in_cur_ifi;
            }
            else
            {
                ps_est_sad->u4_n_p_frm_ifi_avg_sad = 0;
            }
            /* Push the (n-1)th average SAD to the (n-2)th average SAD  */
            ps_est_sad->u4_n_2_p_frm_ifi_avg_sad =
                            ps_est_sad->u4_n_1_p_frm_ifi_avg_sad;
            /* Push the nth average SAD to the (n-1)th average SAD */
            ps_est_sad->u4_n_1_p_frm_ifi_avg_sad =
                            ps_est_sad->u4_n_p_frm_ifi_avg_sad;
            /* Reset SAD and number of P frames */
            ps_est_sad->u4_n_p_frm_ifi_avg_sad = 0;
            ps_est_sad->i4_num_p_frm_in_cur_ifi = 0;
        }
        else
        {
            ps_est_sad->u4_n_p_frm_ifi_avg_sad += u4_actual_sad;
            ps_est_sad->i4_num_p_frm_in_cur_ifi++;
        }
    }
}

void irc_update_actual_sad_for_intra(est_sad_t *ps_est_sad,
                                     WORD32 i4_intra_frm_cost)
{
    if(!(ps_est_sad->i4_use_est_intra_sad))
    {
        irc_update_actual_sad(ps_est_sad, i4_intra_frm_cost, I_PIC);
    }
}