/* * RAW EVC video demuxer * * Copyright (c) 2021 Dawid Kozinski <d.kozinski@samsung.com> * * 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 "libavcodec/evc.h"#include "libavcodec/bsf.h" #include "libavutil/opt.h" #include "avformat.h"#include "avio_internal.h"#include "demux.h"#include "evc.h"#include "internal.h"  #define RAW_PACKET_SIZE 1024 typedef struct EVCDemuxContext {    const AVClass *class;    AVRational framerate;     AVBSFContext *bsf; } EVCDemuxContext; #define DEC AV_OPT_FLAG_DECODING_PARAM#define OFFSET(x) offsetof(EVCDemuxContext, x)static const AVOption evc_options[] = {    { "framerate", "", OFFSET(framerate), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, INT_MAX, DEC},    { NULL },};#undef OFFSET static const AVClass evc_demuxer_class = {    .class_name = "EVC Annex B demuxer",    .item_name  = av_default_item_name,    .option     = evc_options,    .version    = LIBAVUTIL_VERSION_INT,}; static int annexb_probe(const AVProbeData *p){    int nalu_type;    size_t nalu_size;    int got_sps = 0, got_pps = 0, got_idr = 0, got_nonidr = 0;    const unsigned char *bits = p->buf;    int bytes_to_read = p->buf_size;     while (bytes_to_read > EVC_NALU_LENGTH_PREFIX_SIZE) {         nalu_size = evc_read_nal_unit_length(bits, EVC_NALU_LENGTH_PREFIX_SIZE);        if (nalu_size == 0) break;         bits += EVC_NALU_LENGTH_PREFIX_SIZE;        bytes_to_read -= EVC_NALU_LENGTH_PREFIX_SIZE;         if(bytes_to_read < nalu_size) break;         nalu_type = evc_get_nalu_type(bits, bytes_to_read);         if (nalu_type == EVC_SPS_NUT)            got_sps++;        else if (nalu_type == EVC_PPS_NUT)            got_pps++;        else if (nalu_type == EVC_IDR_NUT )            got_idr++;        else if (nalu_type == EVC_NOIDR_NUT)            got_nonidr++;         bits += nalu_size;        bytes_to_read -= nalu_size;    }     if (got_sps && got_pps && (got_idr || got_nonidr > 3))        return AVPROBE_SCORE_EXTENSION + 1;  // 1 more than .mpg     return 0;} static int evc_read_header(AVFormatContext *s){    AVStream *st;    FFStream *sti;    const AVBitStreamFilter *filter = av_bsf_get_by_name("evc_frame_merge");    EVCDemuxContext *c = s->priv_data;    int ret = 0;     st = avformat_new_stream(s, NULL);    if (!st) {        ret = AVERROR(ENOMEM);        goto fail;    }    sti = ffstream(st);     st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;    st->codecpar->codec_id = AV_CODEC_ID_EVC;     // This causes sending to the parser full frames, not chunks of data    // The flag PARSER_FLAG_COMPLETE_FRAMES will be set in demux.c (demux.c: 1316)    sti->need_parsing = AVSTREAM_PARSE_HEADERS;     st->avg_frame_rate = c->framerate;     // taken from rawvideo demuxers    avpriv_set_pts_info(st, 64, 1, 1200000);     ret = av_bsf_alloc(filter, &c->bsf);    if (ret < 0)        return ret;     ret = avcodec_parameters_copy(c->bsf->par_in, st->codecpar);    if (ret < 0)        return ret;     ret = av_bsf_init(c->bsf);    if (ret < 0)        return ret; fail:    return ret;} static int evc_read_packet(AVFormatContext *s, AVPacket *pkt){    int ret;    uint32_t nalu_size;    int au_end_found = 0;    EVCDemuxContext *const c = s->priv_data;     while(!au_end_found) {        uint8_t buf[EVC_NALU_LENGTH_PREFIX_SIZE];         if (avio_feof(s->pb))            goto end;         ret = ffio_ensure_seekback(s->pb, EVC_NALU_LENGTH_PREFIX_SIZE);        if (ret < 0)            return ret;         ret = avio_read(s->pb, buf, EVC_NALU_LENGTH_PREFIX_SIZE);        if (ret < 0)            return ret;        if (ret != EVC_NALU_LENGTH_PREFIX_SIZE)            return AVERROR_INVALIDDATA;         nalu_size = evc_read_nal_unit_length(buf, EVC_NALU_LENGTH_PREFIX_SIZE);        if (!nalu_size || nalu_size > INT_MAX)            return AVERROR_INVALIDDATA;         avio_seek(s->pb, -EVC_NALU_LENGTH_PREFIX_SIZE, SEEK_CUR);         ret = av_get_packet(s->pb, pkt, nalu_size + EVC_NALU_LENGTH_PREFIX_SIZE);        if (ret < 0)            return ret;        if (ret != (nalu_size + EVC_NALU_LENGTH_PREFIX_SIZE))            return AVERROR_INVALIDDATA; end:        ret = av_bsf_send_packet(c->bsf, pkt);        if (ret < 0) {            av_log(s, AV_LOG_ERROR, "Failed to send packet to "                   "evc_frame_merge filter\n");            return ret;        }         ret = av_bsf_receive_packet(c->bsf, pkt);        if (ret < 0 && ret != AVERROR(EAGAIN) && ret != AVERROR_EOF)            av_log(s, AV_LOG_ERROR, "evc_frame_merge filter failed to "                   "send output packet\n");         if (ret != AVERROR(EAGAIN))            au_end_found = 1;    }     return ret;} static int evc_read_close(AVFormatContext *s){    EVCDemuxContext *const c = s->priv_data;     av_bsf_free(&c->bsf);    return 0;} const FFInputFormat ff_evc_demuxer = {    .p.name         = "evc",    .p.long_name    = NULL_IF_CONFIG_SMALL("EVC Annex B"),    .p.extensions   = "evc",    .p.flags        = AVFMT_GENERIC_INDEX | AVFMT_NOTIMESTAMPS,    .p.priv_class   = &evc_demuxer_class,    .read_probe     = annexb_probe,    .read_header    = evc_read_header, // annexb_read_header    .read_packet    = evc_read_packet, // annexb_read_packet    .read_close     = evc_read_close,    .flags_internal = FF_INFMT_FLAG_INIT_CLEANUP,    .raw_codec_id   = AV_CODEC_ID_EVC,    .priv_data_size = sizeof(EVCDemuxContext),};