[libav.git] / libavcodec / h264_ps.c

/*
 * H.26L/H.264/AVC/JVT/14496-10/... parameter set decoding
 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
 *
 * This file is part of Libav.
 *
 * Libav is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * Libav is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * H.264 / AVC / MPEG4 part10 parameter set decoding.
 * @author Michael Niedermayer <michaelni@gmx.at>
 */

#include "libavutil/imgutils.h"
#include "internal.h"
#include "avcodec.h"
#include "h264.h"
#include "h264data.h" //FIXME FIXME FIXME (just for zigzag_scan)
#include "golomb.h"

#define MAX_LOG2_MAX_FRAME_NUM    (12 + 4)
#define MIN_LOG2_MAX_FRAME_NUM    4

static const AVRational pixel_aspect[17] = {
    {   0,  1 },
    {   1,  1 },
    {  12, 11 },
    {  10, 11 },
    {  16, 11 },
    {  40, 33 },
    {  24, 11 },
    {  20, 11 },
    {  32, 11 },
    {  80, 33 },
    {  18, 11 },
    {  15, 11 },
    {  64, 33 },
    { 160, 99 },
    {   4,  3 },
    {   3,  2 },
    {   2,  1 },
};

#define QP(qP, depth) ((qP) + 6 * ((depth) - 8))

#define CHROMA_QP_TABLE_END(d)                                          \
    QP(0,  d), QP(1,  d), QP(2,  d), QP(3,  d), QP(4,  d), QP(5,  d),   \
    QP(6,  d), QP(7,  d), QP(8,  d), QP(9,  d), QP(10, d), QP(11, d),   \
    QP(12, d), QP(13, d), QP(14, d), QP(15, d), QP(16, d), QP(17, d),   \
    QP(18, d), QP(19, d), QP(20, d), QP(21, d), QP(22, d), QP(23, d),   \
    QP(24, d), QP(25, d), QP(26, d), QP(27, d), QP(28, d), QP(29, d),   \
    QP(29, d), QP(30, d), QP(31, d), QP(32, d), QP(32, d), QP(33, d),   \
    QP(34, d), QP(34, d), QP(35, d), QP(35, d), QP(36, d), QP(36, d),   \
    QP(37, d), QP(37, d), QP(37, d), QP(38, d), QP(38, d), QP(38, d),   \
    QP(39, d), QP(39, d), QP(39, d), QP(39, d)

const uint8_t ff_h264_chroma_qp[3][QP_MAX_NUM + 1] = {
    { CHROMA_QP_TABLE_END(8) },
    { 0, 1, 2, 3, 4, 5,
      CHROMA_QP_TABLE_END(9) },
    { 0, 1, 2, 3, 4, 5,
      6, 7, 8, 9, 10, 11,
      CHROMA_QP_TABLE_END(10) },
};

static const uint8_t default_scaling4[2][16] = {
    {  6, 13, 20, 28, 13, 20, 28, 32,
      20, 28, 32, 37, 28, 32, 37, 42 },
    { 10, 14, 20, 24, 14, 20, 24, 27,
      20, 24, 27, 30, 24, 27, 30, 34 }
};

static const uint8_t default_scaling8[2][64] = {
    {  6, 10, 13, 16, 18, 23, 25, 27,
      10, 11, 16, 18, 23, 25, 27, 29,
      13, 16, 18, 23, 25, 27, 29, 31,
      16, 18, 23, 25, 27, 29, 31, 33,
      18, 23, 25, 27, 29, 31, 33, 36,
      23, 25, 27, 29, 31, 33, 36, 38,
      25, 27, 29, 31, 33, 36, 38, 40,
      27, 29, 31, 33, 36, 38, 40, 42 },
    {  9, 13, 15, 17, 19, 21, 22, 24,
      13, 13, 17, 19, 21, 22, 24, 25,
      15, 17, 19, 21, 22, 24, 25, 27,
      17, 19, 21, 22, 24, 25, 27, 28,
      19, 21, 22, 24, 25, 27, 28, 30,
      21, 22, 24, 25, 27, 28, 30, 32,
      22, 24, 25, 27, 28, 30, 32, 33,
      24, 25, 27, 28, 30, 32, 33, 35 }
};

static inline int decode_hrd_parameters(H264Context *h, SPS *sps)
{
    int cpb_count, i;
    cpb_count = get_ue_golomb_31(&h->gb) + 1;

    if (cpb_count > 32U) {
        av_log(h->avctx, AV_LOG_ERROR, "cpb_count %d invalid\n", cpb_count);
        return AVERROR_INVALIDDATA;
    }

    get_bits(&h->gb, 4); /* bit_rate_scale */
    get_bits(&h->gb, 4); /* cpb_size_scale */
    for (i = 0; i < cpb_count; i++) {
        get_ue_golomb_long(&h->gb); /* bit_rate_value_minus1 */
        get_ue_golomb_long(&h->gb); /* cpb_size_value_minus1 */
        get_bits1(&h->gb);          /* cbr_flag */
    }
    sps->initial_cpb_removal_delay_length = get_bits(&h->gb, 5) + 1;
    sps->cpb_removal_delay_length         = get_bits(&h->gb, 5) + 1;
    sps->dpb_output_delay_length          = get_bits(&h->gb, 5) + 1;
    sps->time_offset_length               = get_bits(&h->gb, 5);
    sps->cpb_cnt                          = cpb_count;
    return 0;
}

static inline int decode_vui_parameters(H264Context *h, SPS *sps)
{
    int aspect_ratio_info_present_flag;
    unsigned int aspect_ratio_idc;

    aspect_ratio_info_present_flag = get_bits1(&h->gb);

    if (aspect_ratio_info_present_flag) {
        aspect_ratio_idc = get_bits(&h->gb, 8);
        if (aspect_ratio_idc == EXTENDED_SAR) {
            sps->sar.num = get_bits(&h->gb, 16);
            sps->sar.den = get_bits(&h->gb, 16);
        } else if (aspect_ratio_idc < FF_ARRAY_ELEMS(pixel_aspect)) {
            sps->sar = pixel_aspect[aspect_ratio_idc];
        } else {
            av_log(h->avctx, AV_LOG_ERROR, "illegal aspect ratio\n");
            return AVERROR_INVALIDDATA;
        }
    } else {
        sps->sar.num =
        sps->sar.den = 0;
    }

    if (get_bits1(&h->gb))      /* overscan_info_present_flag */
        get_bits1(&h->gb);      /* overscan_appropriate_flag */

    sps->video_signal_type_present_flag = get_bits1(&h->gb);
    if (sps->video_signal_type_present_flag) {
        get_bits(&h->gb, 3);                 /* video_format */
        sps->full_range = get_bits1(&h->gb); /* video_full_range_flag */

        sps->colour_description_present_flag = get_bits1(&h->gb);
        if (sps->colour_description_present_flag) {
            sps->color_primaries = get_bits(&h->gb, 8); /* colour_primaries */
            sps->color_trc       = get_bits(&h->gb, 8); /* transfer_characteristics */
            sps->colorspace      = get_bits(&h->gb, 8); /* matrix_coefficients */
            if (sps->color_primaries >= AVCOL_PRI_NB)
                sps->color_primaries = AVCOL_PRI_UNSPECIFIED;
            if (sps->color_trc >= AVCOL_TRC_NB)
                sps->color_trc = AVCOL_TRC_UNSPECIFIED;
            if (sps->colorspace >= AVCOL_SPC_NB)
                sps->colorspace = AVCOL_SPC_UNSPECIFIED;
        }
    }

    /* chroma_location_info_present_flag */
    if (get_bits1(&h->gb)) {
        /* chroma_sample_location_type_top_field */
        h->avctx->chroma_sample_location = get_ue_golomb(&h->gb) + 1;
        get_ue_golomb(&h->gb);  /* chroma_sample_location_type_bottom_field */
    }

    sps->timing_info_present_flag = get_bits1(&h->gb);
    if (sps->timing_info_present_flag) {
        sps->num_units_in_tick = get_bits_long(&h->gb, 32);
        sps->time_scale        = get_bits_long(&h->gb, 32);
        if (!sps->num_units_in_tick || !sps->time_scale) {
            av_log(h->avctx, AV_LOG_ERROR,
                   "time_scale/num_units_in_tick invalid or unsupported (%d/%d)\n",
                   sps->time_scale, sps->num_units_in_tick);
            return AVERROR_INVALIDDATA;
        }
        sps->fixed_frame_rate_flag = get_bits1(&h->gb);
    }

    sps->nal_hrd_parameters_present_flag = get_bits1(&h->gb);
    if (sps->nal_hrd_parameters_present_flag)
        if (decode_hrd_parameters(h, sps) < 0)
            return AVERROR_INVALIDDATA;
    sps->vcl_hrd_parameters_present_flag = get_bits1(&h->gb);
    if (sps->vcl_hrd_parameters_present_flag)
        if (decode_hrd_parameters(h, sps) < 0)
            return AVERROR_INVALIDDATA;
    if (sps->nal_hrd_parameters_present_flag ||
        sps->vcl_hrd_parameters_present_flag)
        get_bits1(&h->gb);     /* low_delay_hrd_flag */
    sps->pic_struct_present_flag = get_bits1(&h->gb);

    sps->bitstream_restriction_flag = get_bits1(&h->gb);
    if (sps->bitstream_restriction_flag) {
        get_bits1(&h->gb);     /* motion_vectors_over_pic_boundaries_flag */
        get_ue_golomb(&h->gb); /* max_bytes_per_pic_denom */
        get_ue_golomb(&h->gb); /* max_bits_per_mb_denom */
        get_ue_golomb(&h->gb); /* log2_max_mv_length_horizontal */
        get_ue_golomb(&h->gb); /* log2_max_mv_length_vertical */
        sps->num_reorder_frames = get_ue_golomb(&h->gb);
        get_ue_golomb(&h->gb); /*max_dec_frame_buffering*/

        if (get_bits_left(&h->gb) < 0) {
            sps->num_reorder_frames         = 0;
            sps->bitstream_restriction_flag = 0;
        }

        if (sps->num_reorder_frames > 16U
            /* max_dec_frame_buffering || max_dec_frame_buffering > 16 */) {
            av_log(h->avctx, AV_LOG_ERROR,
                   "Clipping illegal num_reorder_frames %d\n",
                   sps->num_reorder_frames);
            sps->num_reorder_frames = 16;
            return AVERROR_INVALIDDATA;
        }
    }
    if (get_bits_left(&h->gb) < 0) {
        av_log(h->avctx, AV_LOG_ERROR,
               "Overread VUI by %d bits\n", -get_bits_left(&h->gb));
        return AVERROR_INVALIDDATA;
    }

    return 0;
}

static void decode_scaling_list(H264Context *h, uint8_t *factors, int size,
                                const uint8_t *jvt_list,
                                const uint8_t *fallback_list)
{
    int i, last = 8, next = 8;
    const uint8_t *scan = size == 16 ? zigzag_scan : ff_zigzag_direct;
    if (!get_bits1(&h->gb)) /* matrix not written, we use the predicted one */
        memcpy(factors, fallback_list, size * sizeof(uint8_t));
    else
        for (i = 0; i < size; i++) {
            if (next)
                next = (last + get_se_golomb(&h->gb)) & 0xff;
            if (!i && !next) { /* matrix not written, we use the preset one */
                memcpy(factors, jvt_list, size * sizeof(uint8_t));
                break;
            }
            last = factors[scan[i]] = next ? next : last;
        }
}

static void decode_scaling_matrices(H264Context *h, SPS *sps,
                                    PPS *pps, int is_sps,
                                    uint8_t(*scaling_matrix4)[16],
                                    uint8_t(*scaling_matrix8)[64])
{
    int fallback_sps = !is_sps && sps->scaling_matrix_present;
    const uint8_t *fallback[4] = {
        fallback_sps ? sps->scaling_matrix4[0] : default_scaling4[0],
        fallback_sps ? sps->scaling_matrix4[3] : default_scaling4[1],
        fallback_sps ? sps->scaling_matrix8[0] : default_scaling8[0],
        fallback_sps ? sps->scaling_matrix8[3] : default_scaling8[1]
    };
    if (get_bits1(&h->gb)) {
        sps->scaling_matrix_present |= is_sps;
        decode_scaling_list(h, scaling_matrix4[0], 16, default_scaling4[0], fallback[0]);        // Intra, Y
        decode_scaling_list(h, scaling_matrix4[1], 16, default_scaling4[0], scaling_matrix4[0]); // Intra, Cr
        decode_scaling_list(h, scaling_matrix4[2], 16, default_scaling4[0], scaling_matrix4[1]); // Intra, Cb
        decode_scaling_list(h, scaling_matrix4[3], 16, default_scaling4[1], fallback[1]);        // Inter, Y
        decode_scaling_list(h, scaling_matrix4[4], 16, default_scaling4[1], scaling_matrix4[3]); // Inter, Cr
        decode_scaling_list(h, scaling_matrix4[5], 16, default_scaling4[1], scaling_matrix4[4]); // Inter, Cb
        if (is_sps || pps->transform_8x8_mode) {
            decode_scaling_list(h, scaling_matrix8[0], 64, default_scaling8[0], fallback[2]); // Intra, Y
            if (sps->chroma_format_idc == 3) {
                decode_scaling_list(h, scaling_matrix8[1], 64, default_scaling8[0], scaling_matrix8[0]); // Intra, Cr
                decode_scaling_list(h, scaling_matrix8[2], 64, default_scaling8[0], scaling_matrix8[1]); // Intra, Cb
            }
            decode_scaling_list(h, scaling_matrix8[3], 64, default_scaling8[1], fallback[3]); // Inter, Y
            if (sps->chroma_format_idc == 3) {
                decode_scaling_list(h, scaling_matrix8[4], 64, default_scaling8[1], scaling_matrix8[3]); // Inter, Cr
                decode_scaling_list(h, scaling_matrix8[5], 64, default_scaling8[1], scaling_matrix8[4]); // Inter, Cb
            }
        }
    }
}

int ff_h264_decode_seq_parameter_set(H264Context *h)
{
    int profile_idc, level_idc, constraint_set_flags = 0;
    unsigned int sps_id;
    int i, log2_max_frame_num_minus4;
    SPS *sps;

    profile_idc           = get_bits(&h->gb, 8);
    constraint_set_flags |= get_bits1(&h->gb) << 0;   // constraint_set0_flag
    constraint_set_flags |= get_bits1(&h->gb) << 1;   // constraint_set1_flag
    constraint_set_flags |= get_bits1(&h->gb) << 2;   // constraint_set2_flag
    constraint_set_flags |= get_bits1(&h->gb) << 3;   // constraint_set3_flag
    get_bits(&h->gb, 4); // reserved
    level_idc = get_bits(&h->gb, 8);
    sps_id    = get_ue_golomb_31(&h->gb);

    if (sps_id >= MAX_SPS_COUNT) {
        av_log(h->avctx, AV_LOG_ERROR, "sps_id (%d) out of range\n", sps_id);
        return AVERROR_INVALIDDATA;
    }
    sps = av_mallocz(sizeof(SPS));
    if (!sps)
        return AVERROR(ENOMEM);

    sps->time_offset_length   = 24;
    sps->profile_idc          = profile_idc;
    sps->constraint_set_flags = constraint_set_flags;
    sps->level_idc            = level_idc;

    memset(sps->scaling_matrix4, 16, sizeof(sps->scaling_matrix4));
    memset(sps->scaling_matrix8, 16, sizeof(sps->scaling_matrix8));
    sps->scaling_matrix_present = 0;

    if (sps->profile_idc == 100 || sps->profile_idc == 110 ||
        sps->profile_idc == 122 || sps->profile_idc == 244 ||
        sps->profile_idc ==  44 || sps->profile_idc ==  83 ||
        sps->profile_idc ==  86 || sps->profile_idc == 118 ||
        sps->profile_idc == 128 || sps->profile_idc == 144) {
        sps->chroma_format_idc = get_ue_golomb_31(&h->gb);
        if (sps->chroma_format_idc > 3) {
            av_log(h->avctx, AV_LOG_ERROR,
                   "chroma_format_idc (%u) out of range\n",
                   sps->chroma_format_idc);
            goto fail;
        } else if (sps->chroma_format_idc == 3) {
            sps->residual_color_transform_flag = get_bits1(&h->gb);
        }
        sps->bit_depth_luma   = get_ue_golomb(&h->gb) + 8;
        sps->bit_depth_chroma = get_ue_golomb(&h->gb) + 8;
        if (sps->bit_depth_chroma != sps->bit_depth_luma) {
            avpriv_request_sample(h->avctx,
                                  "Different chroma and luma bit depth");
            goto fail;
        }
        sps->transform_bypass = get_bits1(&h->gb);
        decode_scaling_matrices(h, sps, NULL, 1,
                                sps->scaling_matrix4, sps->scaling_matrix8);
    } else {
        sps->chroma_format_idc = 1;
        sps->bit_depth_luma    = 8;
        sps->bit_depth_chroma  = 8;
    }

    log2_max_frame_num_minus4 = get_ue_golomb(&h->gb);
    if (log2_max_frame_num_minus4 < MIN_LOG2_MAX_FRAME_NUM - 4 ||
        log2_max_frame_num_minus4 > MAX_LOG2_MAX_FRAME_NUM - 4) {
        av_log(h->avctx, AV_LOG_ERROR,
               "log2_max_frame_num_minus4 out of range (0-12): %d\n",
               log2_max_frame_num_minus4);
        goto fail;
    }
    sps->log2_max_frame_num = log2_max_frame_num_minus4 + 4;

    sps->poc_type = get_ue_golomb_31(&h->gb);

    if (sps->poc_type == 0) { // FIXME #define
        sps->log2_max_poc_lsb = get_ue_golomb(&h->gb) + 4;
    } else if (sps->poc_type == 1) { // FIXME #define
        sps->delta_pic_order_always_zero_flag = get_bits1(&h->gb);
        sps->offset_for_non_ref_pic           = get_se_golomb(&h->gb);
        sps->offset_for_top_to_bottom_field   = get_se_golomb(&h->gb);
        sps->poc_cycle_length                 = get_ue_golomb(&h->gb);

        if ((unsigned)sps->poc_cycle_length >=
            FF_ARRAY_ELEMS(sps->offset_for_ref_frame)) {
            av_log(h->avctx, AV_LOG_ERROR,
                   "poc_cycle_length overflow %u\n", sps->poc_cycle_length);
            goto fail;
        }

        for (i = 0; i < sps->poc_cycle_length; i++)
            sps->offset_for_ref_frame[i] = get_se_golomb(&h->gb);
    } else if (sps->poc_type != 2) {
        av_log(h->avctx, AV_LOG_ERROR, "illegal POC type %d\n", sps->poc_type);
        goto fail;
    }

    sps->ref_frame_count = get_ue_golomb_31(&h->gb);
    if (sps->ref_frame_count > MAX_PICTURE_COUNT - 2 ||
        sps->ref_frame_count >= 32U) {
        av_log(h->avctx, AV_LOG_ERROR, "too many reference frames\n");
        goto fail;
    }
    sps->gaps_in_frame_num_allowed_flag = get_bits1(&h->gb);
    sps->mb_width                       = get_ue_golomb(&h->gb) + 1;
    sps->mb_height                      = get_ue_golomb(&h->gb) + 1;
    if ((unsigned)sps->mb_width  >= INT_MAX / 16 ||
        (unsigned)sps->mb_height >= INT_MAX / 16 ||
        av_image_check_size(16 * sps->mb_width,
                            16 * sps->mb_height, 0, h->avctx)) {
        av_log(h->avctx, AV_LOG_ERROR, "mb_width/height overflow\n");
        goto fail;
    }

    sps->frame_mbs_only_flag = get_bits1(&h->gb);
    if (!sps->frame_mbs_only_flag)
        sps->mb_aff = get_bits1(&h->gb);
    else
        sps->mb_aff = 0;

    sps->direct_8x8_inference_flag = get_bits1(&h->gb);
    if (!sps->frame_mbs_only_flag && !sps->direct_8x8_inference_flag) {
        av_log(h->avctx, AV_LOG_ERROR,
               "This stream was generated by a broken encoder, invalid 8x8 inference\n");
        goto fail;
    }

#ifndef ALLOW_INTERLACE
    if (sps->mb_aff)
        av_log(h->avctx, AV_LOG_ERROR,
               "MBAFF support not included; enable it at compile-time.\n");
#endif
    sps->crop = get_bits1(&h->gb);
    if (sps->crop) {
        int crop_left   = get_ue_golomb(&h->gb);
        int crop_right  = get_ue_golomb(&h->gb);
        int crop_top    = get_ue_golomb(&h->gb);
        int crop_bottom = get_ue_golomb(&h->gb);

        if (h->avctx->flags2 & CODEC_FLAG2_IGNORE_CROP) {
            av_log(h->avctx, AV_LOG_DEBUG, "discarding sps cropping, original "
                                           "values are l:%u r:%u t:%u b:%u\n",
                   crop_left, crop_right, crop_top, crop_bottom);

            sps->crop_left   =
            sps->crop_right  =
            sps->crop_top    =
            sps->crop_bottom = 0;
        } else {
            int vsub   = (sps->chroma_format_idc == 1) ? 1 : 0;
            int hsub   = (sps->chroma_format_idc == 1 ||
                          sps->chroma_format_idc == 2) ? 1 : 0;
            int step_x = 1 << hsub;
            int step_y = (2 - sps->frame_mbs_only_flag) << vsub;

            if (crop_left & (0x1F >> (sps->bit_depth_luma > 8)) &&
                !(h->avctx->flags & CODEC_FLAG_UNALIGNED)) {
                crop_left &= ~(0x1F >> (sps->bit_depth_luma > 8));
                av_log(h->avctx, AV_LOG_WARNING,
                       "Reducing left cropping to %d "
                       "chroma samples to preserve alignment.\n",
                       crop_left);
            }

            sps->crop_left   = crop_left   * step_x;
            sps->crop_right  = crop_right  * step_x;
            sps->crop_top    = crop_top    * step_y;
            sps->crop_bottom = crop_bottom * step_y;
        }
    } else {
        sps->crop_left   =
        sps->crop_right  =
        sps->crop_top    =
        sps->crop_bottom =
        sps->crop        = 0;
    }

    sps->vui_parameters_present_flag = get_bits1(&h->gb);
    if (sps->vui_parameters_present_flag) {
        int ret = decode_vui_parameters(h, sps);
        if (ret < 0 && h->avctx->err_recognition & AV_EF_EXPLODE)
            goto fail;
    }

    if (!sps->sar.den)
        sps->sar.den = 1;

    if (h->avctx->debug & FF_DEBUG_PICT_INFO) {
        static const char csp[4][5] = { "Gray", "420", "422", "444" };
        av_log(h->avctx, AV_LOG_DEBUG,
               "sps:%u profile:%d/%d poc:%d ref:%d %dx%d %s %s crop:%d/%d/%d/%d %s %s %d/%d\n",
               sps_id, sps->profile_idc, sps->level_idc,
               sps->poc_type,
               sps->ref_frame_count,
               sps->mb_width, sps->mb_height,
               sps->frame_mbs_only_flag ? "FRM" : (sps->mb_aff ? "MB-AFF" : "PIC-AFF"),
               sps->direct_8x8_inference_flag ? "8B8" : "",
               sps->crop_left, sps->crop_right,
               sps->crop_top, sps->crop_bottom,
               sps->vui_parameters_present_flag ? "VUI" : "",
               csp[sps->chroma_format_idc],
               sps->timing_info_present_flag ? sps->num_units_in_tick : 0,
               sps->timing_info_present_flag ? sps->time_scale : 0);
    }
    sps->new = 1;

    av_free(h->sps_buffers[sps_id]);
    h->sps_buffers[sps_id] = sps;
    h->sps                 = *sps;
    h->current_sps_id      = sps_id;

    return 0;

fail:
    av_free(sps);
    return -1;
}

static void build_qp_table(PPS *pps, int t, int index, const int depth)
{
    int i;
    const int max_qp = 51 + 6 * (depth - 8);
    for (i = 0; i < max_qp + 1; i++)
        pps->chroma_qp_table[t][i] =
            ff_h264_chroma_qp[depth - 8][av_clip(i + index, 0, max_qp)];
}

int ff_h264_decode_picture_parameter_set(H264Context *h, int bit_length)
{
    unsigned int pps_id = get_ue_golomb(&h->gb);
    PPS *pps;
    const int qp_bd_offset = 6 * (h->sps.bit_depth_luma - 8);
    int bits_left;

    if (pps_id >= MAX_PPS_COUNT) {
        av_log(h->avctx, AV_LOG_ERROR, "pps_id (%d) out of range\n", pps_id);
        return AVERROR_INVALIDDATA;
    } else if (h->sps.bit_depth_luma > 10) {
        av_log(h->avctx, AV_LOG_ERROR,
               "Unimplemented luma bit depth=%d (max=10)\n",
               h->sps.bit_depth_luma);
        return AVERROR_PATCHWELCOME;
    }

    pps = av_mallocz(sizeof(PPS));
    if (!pps)
        return AVERROR(ENOMEM);
    pps->sps_id = get_ue_golomb_31(&h->gb);
    if ((unsigned)pps->sps_id >= MAX_SPS_COUNT ||
        h->sps_buffers[pps->sps_id] == NULL) {
        av_log(h->avctx, AV_LOG_ERROR, "sps_id out of range\n");
        goto fail;
    }

    pps->cabac             = get_bits1(&h->gb);
    pps->pic_order_present = get_bits1(&h->gb);
    pps->slice_group_count = get_ue_golomb(&h->gb) + 1;
    if (pps->slice_group_count > 1) {
        pps->mb_slice_group_map_type = get_ue_golomb(&h->gb);
        av_log(h->avctx, AV_LOG_ERROR, "FMO not supported\n");
        switch (pps->mb_slice_group_map_type) {
        case 0:
#if 0
    |       for (i = 0; i <= num_slice_groups_minus1; i++)  |   |      |
    |           run_length[i]                               |1  |ue(v) |
#endif
            break;
        case 2:
#if 0
    |       for (i = 0; i < num_slice_groups_minus1; i++) { |   |      |
    |           top_left_mb[i]                              |1  |ue(v) |
    |           bottom_right_mb[i]                          |1  |ue(v) |
    |       }                                               |   |      |
#endif
            break;
        case 3:
        case 4:
        case 5:
#if 0
    |       slice_group_change_direction_flag               |1  |u(1)  |
    |       slice_group_change_rate_minus1                  |1  |ue(v) |
#endif
            break;
        case 6:
#if 0
    |       slice_group_id_cnt_minus1                       |1  |ue(v) |
    |       for (i = 0; i <= slice_group_id_cnt_minus1; i++)|   |      |
    |           slice_group_id[i]                           |1  |u(v)  |
#endif
            break;
        }
    }
    pps->ref_count[0] = get_ue_golomb(&h->gb) + 1;
    pps->ref_count[1] = get_ue_golomb(&h->gb) + 1;
    if (pps->ref_count[0] - 1 > 32 - 1 || pps->ref_count[1] - 1 > 32 - 1) {
        av_log(h->avctx, AV_LOG_ERROR, "reference overflow (pps)\n");
        goto fail;
    }

    pps->weighted_pred                        = get_bits1(&h->gb);
    pps->weighted_bipred_idc                  = get_bits(&h->gb, 2);
    pps->init_qp                              = get_se_golomb(&h->gb) + 26 + qp_bd_offset;
    pps->init_qs                              = get_se_golomb(&h->gb) + 26 + qp_bd_offset;
    pps->chroma_qp_index_offset[0]            = get_se_golomb(&h->gb);
    pps->deblocking_filter_parameters_present = get_bits1(&h->gb);
    pps->constrained_intra_pred               = get_bits1(&h->gb);
    pps->redundant_pic_cnt_present            = get_bits1(&h->gb);

    pps->transform_8x8_mode = 0;
    // contents of sps/pps can change even if id doesn't, so reinit
    h->dequant_coeff_pps = -1;
    memcpy(pps->scaling_matrix4, h->sps_buffers[pps->sps_id]->scaling_matrix4,
           sizeof(pps->scaling_matrix4));
    memcpy(pps->scaling_matrix8, h->sps_buffers[pps->sps_id]->scaling_matrix8,
           sizeof(pps->scaling_matrix8));

    bits_left = bit_length - get_bits_count(&h->gb);
    if (bits_left && (bits_left > 8 ||
                      show_bits(&h->gb, bits_left) != 1 << (bits_left - 1))) {
        pps->transform_8x8_mode = get_bits1(&h->gb);
        decode_scaling_matrices(h, h->sps_buffers[pps->sps_id], pps, 0,
                                pps->scaling_matrix4, pps->scaling_matrix8);
        // second_chroma_qp_index_offset
        pps->chroma_qp_index_offset[1] = get_se_golomb(&h->gb);
    } else {
        pps->chroma_qp_index_offset[1] = pps->chroma_qp_index_offset[0];
    }

    build_qp_table(pps, 0, pps->chroma_qp_index_offset[0],
                   h->sps.bit_depth_luma);
    build_qp_table(pps, 1, pps->chroma_qp_index_offset[1],
                   h->sps.bit_depth_luma);
    if (pps->chroma_qp_index_offset[0] != pps->chroma_qp_index_offset[1])
        pps->chroma_qp_diff = 1;

    if (h->avctx->debug & FF_DEBUG_PICT_INFO) {
        av_log(h->avctx, AV_LOG_DEBUG,
               "pps:%u sps:%u %s slice_groups:%d ref:%d/%d %s qp:%d/%d/%d/%d %s %s %s %s\n",
               pps_id, pps->sps_id,
               pps->cabac ? "CABAC" : "CAVLC",
               pps->slice_group_count,
               pps->ref_count[0], pps->ref_count[1],
               pps->weighted_pred ? "weighted" : "",
               pps->init_qp, pps->init_qs, pps->chroma_qp_index_offset[0], pps->chroma_qp_index_offset[1],
               pps->deblocking_filter_parameters_present ? "LPAR" : "",
               pps->constrained_intra_pred ? "CONSTR" : "",
               pps->redundant_pic_cnt_present ? "REDU" : "",
               pps->transform_8x8_mode ? "8x8DCT" : "");
    }

    av_free(h->pps_buffers[pps_id]);
    h->pps_buffers[pps_id] = pps;
    return 0;

fail:
    av_free(pps);
    return -1;
}