/* * Copyright (c) 2021 Paul B Mahol * * 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 */ /** * @file * Change the PTS/DTS timestamps. */ #include "libavutil/opt.h"#include "libavutil/eval.h" #include "bsf.h"#include "bsf_internal.h" static const char *const var_names[] = {    "N",           ///< frame number (starting at zero)    "TS",    "POS",         ///< original position in the file of the frame    "PREV_INPTS",  ///< previous  input PTS    "PREV_INDTS",  ///< previous  input DTS    "PREV_INDURATION", ///< previous input duration    "PREV_OUTPTS", ///< previous output PTS    "PREV_OUTDTS", ///< previous output DTS    "PREV_OUTDURATION", ///< previous output duration    "NEXT_PTS",    ///< next input PTS    "NEXT_DTS",    ///< next input DTS    "NEXT_DURATION", ///< next input duration    "PTS",         ///< original PTS in the file of the frame    "DTS",         ///< original DTS in the file of the frame    "DURATION",    ///< original duration in the file of the frame    "STARTPTS",    ///< PTS at start of movie    "STARTDTS",    ///< DTS at start of movie    "TB",          ///< input timebase of the stream    "TB_OUT",      ///< output timebase of the stream    "SR",          ///< sample rate of the stream    "NOPTS",       ///< The AV_NOPTS_VALUE constant    NULL}; enum var_name {    VAR_N,    VAR_TS,    VAR_POS,    VAR_PREV_INPTS,    VAR_PREV_INDTS,    VAR_PREV_INDUR,    VAR_PREV_OUTPTS,    VAR_PREV_OUTDTS,    VAR_PREV_OUTDUR,    VAR_NEXT_PTS,    VAR_NEXT_DTS,    VAR_NEXT_DUR,    VAR_PTS,    VAR_DTS,    VAR_DURATION,    VAR_STARTPTS,    VAR_STARTDTS,    VAR_TB,    VAR_TB_OUT,    VAR_SR,    VAR_NOPTS,    VAR_VARS_NB}; typedef struct SetTSContext {    const AVClass *class;     char *ts_str;    char *pts_str;    char *dts_str;    char *duration_str;     AVRational time_base;     int64_t frame_number;     double var_values[VAR_VARS_NB];     AVExpr *ts_expr;    AVExpr *pts_expr;    AVExpr *dts_expr;    AVExpr *duration_expr;     AVPacket *prev_inpkt;    AVPacket *prev_outpkt;    AVPacket *cur_pkt;} SetTSContext; static int setts_init(AVBSFContext *ctx){    SetTSContext *s = ctx->priv_data;    int ret;     s->prev_inpkt = av_packet_alloc();    s->prev_outpkt = av_packet_alloc();    s->cur_pkt = av_packet_alloc();    if (!s->prev_inpkt || !s->prev_outpkt || !s->cur_pkt)        return AVERROR(ENOMEM);     if ((ret = av_expr_parse(&s->ts_expr, s->ts_str,                             var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {        av_log(ctx, AV_LOG_ERROR, "Error while parsing ts expression '%s'\n", s->ts_str);        return ret;    }     if ((ret = av_expr_parse(&s->duration_expr, s->duration_str,                             var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {        av_log(ctx, AV_LOG_ERROR, "Error while parsing duration expression '%s'\n", s->duration_str);        return ret;    }     if (s->pts_str) {        if ((ret = av_expr_parse(&s->pts_expr, s->pts_str,                                 var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {            av_log(ctx, AV_LOG_ERROR, "Error while parsing pts expression '%s'\n", s->pts_str);            return ret;        }    }     if (s->dts_str) {        if ((ret = av_expr_parse(&s->dts_expr, s->dts_str,                                 var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {            av_log(ctx, AV_LOG_ERROR, "Error while parsing dts expression '%s'\n", s->dts_str);            return ret;        }    }     if (s->time_base.num > 0 && s->time_base.den > 0)        ctx->time_base_out = s->time_base;     s->frame_number= 0;    s->var_values[VAR_STARTPTS] = AV_NOPTS_VALUE;    s->var_values[VAR_STARTDTS] = AV_NOPTS_VALUE;    s->var_values[VAR_NOPTS] = AV_NOPTS_VALUE;    s->var_values[VAR_TB]    = ctx->time_base_in.den ? av_q2d(ctx->time_base_in) : 0;    s->var_values[VAR_TB_OUT]= ctx->time_base_out.den ? av_q2d(ctx->time_base_out) : 0;    s->var_values[VAR_SR]    = ctx->par_in->sample_rate;     return 0;} static int setts_filter(AVBSFContext *ctx, AVPacket *pkt){    SetTSContext *s = ctx->priv_data;    int64_t new_ts, new_pts, new_dts, new_duration;    int ret;     ret = ff_bsf_get_packet_ref(ctx, pkt);    if (ret < 0 && (ret != AVERROR_EOF || !s->cur_pkt->data))        return ret;     if (!s->cur_pkt->data) {         av_packet_move_ref(s->cur_pkt, pkt);         return AVERROR(EAGAIN);    }     if (s->var_values[VAR_STARTPTS] == AV_NOPTS_VALUE)        s->var_values[VAR_STARTPTS] = s->cur_pkt->pts;     if (s->var_values[VAR_STARTDTS] == AV_NOPTS_VALUE)        s->var_values[VAR_STARTDTS] = s->cur_pkt->dts;     s->var_values[VAR_N]           = s->frame_number++;    s->var_values[VAR_TS]          = s->cur_pkt->dts;    s->var_values[VAR_POS]         = s->cur_pkt->pos;    s->var_values[VAR_PTS]         = s->cur_pkt->pts;    s->var_values[VAR_DTS]         = s->cur_pkt->dts;    s->var_values[VAR_DURATION]    = s->cur_pkt->duration;    s->var_values[VAR_PREV_INPTS]  = s->prev_inpkt->pts;    s->var_values[VAR_PREV_INDTS]  = s->prev_inpkt->dts;    s->var_values[VAR_PREV_INDUR]  = s->prev_inpkt->duration;    s->var_values[VAR_PREV_OUTPTS] = s->prev_outpkt->pts;    s->var_values[VAR_PREV_OUTDTS] = s->prev_outpkt->dts;    s->var_values[VAR_PREV_OUTDUR] = s->prev_outpkt->duration;    s->var_values[VAR_NEXT_PTS]    = pkt->pts;    s->var_values[VAR_NEXT_DTS]    = pkt->dts;    s->var_values[VAR_NEXT_DUR]    = pkt->duration;     new_ts = llrint(av_expr_eval(s->ts_expr, s->var_values, NULL));    new_duration = llrint(av_expr_eval(s->duration_expr, s->var_values, NULL));     if (s->pts_str) {        s->var_values[VAR_TS] = s->cur_pkt->pts;        new_pts = llrint(av_expr_eval(s->pts_expr, s->var_values, NULL));    } else {        new_pts = new_ts;    }     if (s->dts_str) {        s->var_values[VAR_TS] = s->cur_pkt->dts;        new_dts = llrint(av_expr_eval(s->dts_expr, s->var_values, NULL));    } else {        new_dts = new_ts;    }     av_packet_unref(s->prev_inpkt);    av_packet_unref(s->prev_outpkt);    av_packet_move_ref(s->prev_inpkt, s->cur_pkt);    av_packet_move_ref(s->cur_pkt, pkt);     ret = av_packet_ref(pkt, s->prev_inpkt);    if (ret < 0)        return ret;     pkt->pts = new_pts;    pkt->dts = new_dts;    pkt->duration = new_duration;     ret = av_packet_ref(s->prev_outpkt, pkt);    if (ret < 0)        av_packet_unref(pkt);     return ret;} static void setts_close(AVBSFContext *bsf){    SetTSContext *s = bsf->priv_data;     av_packet_free(&s->prev_inpkt);    av_packet_free(&s->prev_outpkt);    av_packet_free(&s->cur_pkt);     av_expr_free(s->ts_expr);    s->ts_expr = NULL;    av_expr_free(s->pts_expr);    s->pts_expr = NULL;    av_expr_free(s->dts_expr);    s->dts_expr = NULL;    av_expr_free(s->duration_expr);    s->duration_expr = NULL;} #define OFFSET(x) offsetof(SetTSContext, x)#define FLAGS (AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_SUBTITLE_PARAM|AV_OPT_FLAG_BSF_PARAM) static const AVOption options[] = {    { "ts",  "set expression for packet PTS and DTS", OFFSET(ts_str),  AV_OPT_TYPE_STRING, {.str="TS"}, 0, 0, FLAGS },    { "pts", "set expression for packet PTS", OFFSET(pts_str), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, FLAGS },    { "dts", "set expression for packet DTS", OFFSET(dts_str), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, FLAGS },    { "duration", "set expression for packet duration", OFFSET(duration_str), AV_OPT_TYPE_STRING, {.str="DURATION"}, 0, 0, FLAGS },    { "time_base", "set output timebase", OFFSET(time_base), AV_OPT_TYPE_RATIONAL, {.dbl=0}, 0, INT_MAX, FLAGS },    { NULL },}; static const AVClass setts_class = {    .class_name = "setts_bsf",    .item_name  = av_default_item_name,    .option     = options,    .version    = LIBAVUTIL_VERSION_INT,}; const FFBitStreamFilter ff_setts_bsf = {    .p.name         = "setts",    .p.priv_class   = &setts_class,    .priv_data_size = sizeof(SetTSContext),    .init           = setts_init,    .close          = setts_close,    .filter         = setts_filter,};