2 * Copyright (c) 2021 Paul B Mahol
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 * Change the PTS/DTS timestamps.
26 #include "libavutil/opt.h"
27 #include "libavutil/eval.h"
31 #include "bsf_internal.h"
33 static const char *const var_names[] = {
34 "N", ///< frame number (starting at zero)
36 "POS", ///< original position in the file of the frame
37 "PREV_INPTS", ///< previous input PTS
38 "PREV_INDTS", ///< previous input DTS
39 "PREV_OUTPTS", ///< previous output PTS
40 "PREV_OUTDTS", ///< previous output DTS
41 "PTS", ///< original PTS in the file of the frame
42 "DTS", ///< original DTS in the file of the frame
43 "STARTPTS", ///< PTS at start of movie
44 "STARTDTS", ///< DTS at start of movie
45 "TB", ///< timebase of the stream
46 "SR", ///< sample rate of the stream
67 typedef struct SetTSContext {
83 double var_values[VAR_VARS_NB];
90 static int setts_init(AVBSFContext *ctx)
92 SetTSContext *s = ctx->priv_data;
95 if ((ret = av_expr_parse(&s->ts_expr, s->ts_str,
96 var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
97 av_log(ctx, AV_LOG_ERROR, "Error while parsing ts expression '%s'\n", s->ts_str);
102 if ((ret = av_expr_parse(&s->pts_expr, s->pts_str,
103 var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
104 av_log(ctx, AV_LOG_ERROR, "Error while parsing pts expression '%s'\n", s->pts_str);
110 if ((ret = av_expr_parse(&s->dts_expr, s->dts_str,
111 var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
112 av_log(ctx, AV_LOG_ERROR, "Error while parsing dts expression '%s'\n", s->dts_str);
118 s->start_pts = AV_NOPTS_VALUE;
119 s->start_dts = AV_NOPTS_VALUE;
120 s->prev_inpts = AV_NOPTS_VALUE;
121 s->prev_indts = AV_NOPTS_VALUE;
122 s->prev_outpts = AV_NOPTS_VALUE;
123 s->prev_outdts = AV_NOPTS_VALUE;
128 static int setts_filter(AVBSFContext *ctx, AVPacket *pkt)
130 SetTSContext *s = ctx->priv_data;
131 int64_t new_ts, new_pts, new_dts;
134 ret = ff_bsf_get_packet_ref(ctx, pkt);
138 if (s->start_pts == AV_NOPTS_VALUE)
139 s->start_pts = pkt->pts;
141 if (s->start_dts == AV_NOPTS_VALUE)
142 s->start_dts = pkt->dts;
144 s->var_values[VAR_N] = s->frame_number++;
145 s->var_values[VAR_TS] = pkt->dts;
146 s->var_values[VAR_POS] = pkt->pos;
147 s->var_values[VAR_PTS] = pkt->pts;
148 s->var_values[VAR_DTS] = pkt->dts;
149 s->var_values[VAR_PREV_INPTS] = s->prev_inpts;
150 s->var_values[VAR_PREV_INDTS] = s->prev_indts;
151 s->var_values[VAR_PREV_OUTPTS] = s->prev_outpts;
152 s->var_values[VAR_PREV_OUTDTS] = s->prev_outdts;
153 s->var_values[VAR_STARTPTS] = s->start_pts;
154 s->var_values[VAR_STARTDTS] = s->start_dts;
155 s->var_values[VAR_TB] = av_q2d(ctx->time_base_out);
156 s->var_values[VAR_SR] = ctx->par_in->sample_rate;
158 new_ts = llrint(av_expr_eval(s->ts_expr, s->var_values, NULL));
161 s->var_values[VAR_TS] = pkt->pts;
162 new_pts = llrint(av_expr_eval(s->pts_expr, s->var_values, NULL));
168 s->var_values[VAR_TS] = pkt->dts;
169 new_dts = llrint(av_expr_eval(s->dts_expr, s->var_values, NULL));
174 s->var_values[VAR_PREV_INPTS] = pkt->pts;
175 s->var_values[VAR_PREV_INDTS] = pkt->dts;
176 s->var_values[VAR_PREV_OUTPTS] = new_pts;
177 s->var_values[VAR_PREV_OUTDTS] = new_dts;
185 static void setts_close(AVBSFContext *bsf)
187 SetTSContext *s = bsf->priv_data;
189 av_expr_free(s->ts_expr);
191 av_expr_free(s->pts_expr);
193 av_expr_free(s->dts_expr);
197 #define OFFSET(x) offsetof(SetTSContext, x)
198 #define FLAGS (AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_SUBTITLE_PARAM|AV_OPT_FLAG_BSF_PARAM)
200 static const AVOption options[] = {
201 { "ts", "set expression for packet PTS and DTS", OFFSET(ts_str), AV_OPT_TYPE_STRING, {.str="TS"}, 0, 0, FLAGS },
202 { "pts", "set expression for packet PTS", OFFSET(pts_str), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, FLAGS },
203 { "dts", "set expression for packet DTS", OFFSET(dts_str), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, FLAGS },
207 static const AVClass setts_class = {
208 .class_name = "setts_bsf",
209 .item_name = av_default_item_name,
211 .version = LIBAVUTIL_VERSION_INT,
214 const AVBitStreamFilter ff_setts_bsf = {
216 .priv_data_size = sizeof(SetTSContext),
217 .priv_class = &setts_class,
219 .close = setts_close,
220 .filter = setts_filter,