sei.c

Go to the documentation of this file.

/*
 * HEVC Supplementary Enhancement Information messages
 *
 * Copyright (C) 2012 - 2013 Guillaume Martres
 * Copyright (C) 2012 - 2013 Gildas Cocherel
 * Copyright (C) 2013 Vittorio Giovara
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg 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.
 *
 * FFmpeg 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 FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */
 
#include "bytestream.h"
#include "golomb.h"
#include "ps.h"
#include "sei.h"
 
static int decode_nal_sei_decoded_picture_hash(HEVCSEIPictureHash *s,
                                               GetByteContext *gb)
{
    int cIdx;
    uint8_t hash_type;
    //uint16_t picture_crc;
    //uint32_t picture_checksum;
    hash_type = bytestream2_get_byte(gb);
 
    for (cIdx = 0; cIdx < 3/*((s->sps->chroma_format_idc == 0) ? 1 : 3)*/; cIdx++) {
        if (hash_type == 0) {
            s->is_md5 = 1;
            bytestream2_get_buffer(gb, s->md5[cIdx], sizeof(s->md5[cIdx]));
        } else if (hash_type == 1) {
            // picture_crc = get_bits(gb, 16);
        } else if (hash_type == 2) {
            // picture_checksum = get_bits_long(gb, 32);
        }
    }
    return 0;
}
 
static int decode_nal_sei_pic_timing(HEVCSEI *s, GetBitContext *gb,
                                     const HEVCParamSets *ps, void *logctx)
{
    HEVCSEIPictureTiming *h = &s->picture_timing;
    const HEVCSPS *sps = ps->sps_list[s->active_seq_parameter_set_id];
 
    if (!sps)
        return AVERROR_INVALIDDATA;
 
    if (sps->vui.frame_field_info_present_flag) {
        int pic_struct = get_bits(gb, 4);
        h->picture_struct = AV_PICTURE_STRUCTURE_UNKNOWN;
        if (pic_struct == 2 || pic_struct == 10 || pic_struct == 12) {
            av_log(logctx, AV_LOG_DEBUG, "BOTTOM Field\n");
            h->picture_struct = AV_PICTURE_STRUCTURE_BOTTOM_FIELD;
        } else if (pic_struct == 1 || pic_struct == 9 || pic_struct == 11) {
            av_log(logctx, AV_LOG_DEBUG, "TOP Field\n");
            h->picture_struct = AV_PICTURE_STRUCTURE_TOP_FIELD;
        } else if (pic_struct == 7) {
            av_log(logctx, AV_LOG_DEBUG, "Frame/Field Doubling\n");
            h->picture_struct = HEVC_SEI_PIC_STRUCT_FRAME_DOUBLING;
        } else if (pic_struct == 8) {
            av_log(logctx, AV_LOG_DEBUG, "Frame/Field Tripling\n");
            h->picture_struct = HEVC_SEI_PIC_STRUCT_FRAME_TRIPLING;
        }
    }
 
    return 0;
}
 
static int decode_nal_sei_active_parameter_sets(HEVCSEI *s, GetBitContext *gb, void *logctx)
{
    int num_sps_ids_minus1;
    unsigned active_seq_parameter_set_id;
 
    get_bits(gb, 4); // active_video_parameter_set_id
    get_bits(gb, 1); // self_contained_cvs_flag
    get_bits(gb, 1); // num_sps_ids_minus1
    num_sps_ids_minus1 = get_ue_golomb_long(gb); // num_sps_ids_minus1
 
    if (num_sps_ids_minus1 < 0 || num_sps_ids_minus1 > 15) {
        av_log(logctx, AV_LOG_ERROR, "num_sps_ids_minus1 %d invalid\n", num_sps_ids_minus1);
        return AVERROR_INVALIDDATA;
    }
 
    active_seq_parameter_set_id = get_ue_golomb_long(gb);
    if (active_seq_parameter_set_id >= HEVC_MAX_SPS_COUNT) {
        av_log(logctx, AV_LOG_ERROR, "active_parameter_set_id %d invalid\n", active_seq_parameter_set_id);
        return AVERROR_INVALIDDATA;
    }
    s->active_seq_parameter_set_id = active_seq_parameter_set_id;
 
    return 0;
}
 
static int decode_nal_sei_timecode(HEVCSEITimeCode *s, GetBitContext *gb)
{
    s->num_clock_ts = get_bits(gb, 2);
 
    for (int i = 0; i < s->num_clock_ts; i++) {
        s->clock_timestamp_flag[i] =  get_bits(gb, 1);
 
        if (s->clock_timestamp_flag[i]) {
            s->units_field_based_flag[i] = get_bits(gb, 1);
            s->counting_type[i]          = get_bits(gb, 5);
            s->full_timestamp_flag[i]    = get_bits(gb, 1);
            s->discontinuity_flag[i]     = get_bits(gb, 1);
            s->cnt_dropped_flag[i]       = get_bits(gb, 1);
 
            s->n_frames[i]               = get_bits(gb, 9);
 
            if (s->full_timestamp_flag[i]) {
                s->seconds_value[i]      = av_clip(get_bits(gb, 6), 0, 59);
                s->minutes_value[i]      = av_clip(get_bits(gb, 6), 0, 59);
                s->hours_value[i]        = av_clip(get_bits(gb, 5), 0, 23);
            } else {
                s->seconds_flag[i] = get_bits(gb, 1);
                if (s->seconds_flag[i]) {
                    s->seconds_value[i] = av_clip(get_bits(gb, 6), 0, 59);
                    s->minutes_flag[i]  = get_bits(gb, 1);
                    if (s->minutes_flag[i]) {
                        s->minutes_value[i] = av_clip(get_bits(gb, 6), 0, 59);
                        s->hours_flag[i] =  get_bits(gb, 1);
                        if (s->hours_flag[i]) {
                            s->hours_value[i] = av_clip(get_bits(gb, 5), 0, 23);
                        }
                    }
                }
            }
 
            s->time_offset_length[i] = get_bits(gb, 5);
            if (s->time_offset_length[i] > 0) {
                s->time_offset_value[i] = get_bits_long(gb, s->time_offset_length[i]);
            }
        }
    }
 
    s->present = 1;
    return 0;
}
 
static int decode_nal_sei_prefix(GetBitContext *gb, GetByteContext *gbyte,
                                 void *logctx, HEVCSEI *s,
                                 const HEVCParamSets *ps, int type)
{
    switch (type) {
    case 256:  // Mismatched value from HM 8.1
        return decode_nal_sei_decoded_picture_hash(&s->picture_hash, gbyte);
    case SEI_TYPE_PIC_TIMING:
        return decode_nal_sei_pic_timing(s, gb, ps, logctx);
    case SEI_TYPE_ACTIVE_PARAMETER_SETS:
        return decode_nal_sei_active_parameter_sets(s, gb, logctx);
    case SEI_TYPE_TIME_CODE:
        return decode_nal_sei_timecode(&s->timecode, gb);
    default: {
        int ret = ff_h2645_sei_message_decode(&s->common, type, AV_CODEC_ID_HEVC,
                                              gb, gbyte, logctx);
        if (ret == FF_H2645_SEI_MESSAGE_UNHANDLED)
            av_log(logctx, AV_LOG_DEBUG, "Skipped PREFIX SEI %d\n", type);
        return ret;
    }
    }
}
 
static int decode_nal_sei_suffix(GetBitContext *gb, GetByteContext *gbyte,
                                 void *logctx, HEVCSEI *s, int type)
{
    switch (type) {
    case SEI_TYPE_DECODED_PICTURE_HASH:
        return decode_nal_sei_decoded_picture_hash(&s->picture_hash, gbyte);
    default:
        av_log(logctx, AV_LOG_DEBUG, "Skipped SUFFIX SEI %d\n", type);
        return 0;
    }
}
 
static int decode_nal_sei_message(GetByteContext *gb, void *logctx, HEVCSEI *s,
                                  const HEVCParamSets *ps, int nal_unit_type)
{
    GetByteContext message_gbyte;
    GetBitContext message_gb;
    int payload_type = 0;
    int payload_size = 0;
    int byte = 0xFF;
    av_unused int ret;
    av_log(logctx, AV_LOG_DEBUG, "Decoding SEI\n");
 
    while (byte == 0xFF) {
        if (bytestream2_get_bytes_left(gb) < 2 || payload_type > INT_MAX - 255)
            return AVERROR_INVALIDDATA;
        byte          = bytestream2_get_byteu(gb);
        payload_type += byte;
    }
    byte = 0xFF;
    while (byte == 0xFF) {
        if (bytestream2_get_bytes_left(gb) < 1 + payload_size)
            return AVERROR_INVALIDDATA;
        byte          = bytestream2_get_byteu(gb);
        payload_size += byte;
    }
    if (bytestream2_get_bytes_left(gb) < payload_size)
        return AVERROR_INVALIDDATA;
    bytestream2_init(&message_gbyte, gb->buffer, payload_size);
    ret = init_get_bits8(&message_gb, gb->buffer, payload_size);
    av_assert1(ret >= 0);
    bytestream2_skipu(gb, payload_size);
    if (nal_unit_type == HEVC_NAL_SEI_PREFIX) {
        return decode_nal_sei_prefix(&message_gb, &message_gbyte,
                                     logctx, s, ps, payload_type);
    } else { /* nal_unit_type == NAL_SEI_SUFFIX */
        return decode_nal_sei_suffix(&message_gb, &message_gbyte,
                                     logctx, s, payload_type);
    }
}
 
int ff_hevc_decode_nal_sei(GetBitContext *gb, void *logctx, HEVCSEI *s,
                           const HEVCParamSets *ps, enum HEVCNALUnitType type)
{
    GetByteContext gbyte;
    int ret;
 
    av_assert1((get_bits_count(gb) % 8) == 0);
    bytestream2_init(&gbyte, gb->buffer + get_bits_count(gb) / 8,
                     get_bits_left(gb) / 8);
 
    do {
        ret = decode_nal_sei_message(&gbyte, logctx, s, ps, type);
        if (ret < 0)
            return ret;
    } while (bytestream2_get_bytes_left(&gbyte) > 0);
    return 1;
}