[FFmpeg-devel] [PATCH] avcodec: add setts bitstream filter
Paul B Mahol
onemda at gmail.com
Tue Feb 9 15:09:21 EET 2021
Signed-off-by: Paul B Mahol <onemda at gmail.com>
---
doc/bitstream_filters.texi | 51 ++++++++
libavcodec/Makefile | 1 +
libavcodec/bitstream_filters.c | 1 +
libavcodec/setts_bsf.c | 215 +++++++++++++++++++++++++++++++++
4 files changed, 268 insertions(+)
create mode 100644 libavcodec/setts_bsf.c
diff --git a/doc/bitstream_filters.texi b/doc/bitstream_filters.texi
index 8a2f55cc41..33a0239030 100644
--- a/doc/bitstream_filters.texi
+++ b/doc/bitstream_filters.texi
@@ -675,6 +675,57 @@ Remove extradata from all frames.
@end table
@end table
+ at section setts
+Set PTS and DTS in packets.
+
+It accepts the following parameters:
+ at table @option
+ at item ts
+ at item pts
+ at item dts
+Set expressions for PTS, DTS or both.
+ at end table
+
+The expressions are evaluated through the eval API and can contain the following
+constants:
+
+ at table @option
+ at item N
+The count of the input packet. Starting from 0.
+
+ at item TS
+The demux timestamp in input in case of @code{ts} or @code{dts} option or presentation
+timestamp in case of @code{pts} option.
+
+ at item POS
+original position in the file of the packet, or undefined if undefined
+for the current packet
+
+ at item DTS
+The demux timestamp in input.
+
+ at item PTS
+The presentation timestamp in input.
+
+ at item STARTDTS
+The DTS of the first packet.
+
+ at item STARTPTS
+The PTS of the first packet.
+
+ at item PREV_INDTS
+The previous input DTS.
+
+ at item PREV_INPTS
+The previous input PTS.
+
+ at item PREV_OUTDTS
+The previous output DTS.
+
+ at item PREV_OUTPTS
+The previous output PTS.
+ at end table
+
@anchor{text2movsub}
@section text2movsub
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index b6f5c5608f..dff446a10b 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -1164,6 +1164,7 @@ OBJS-$(CONFIG_OPUS_METADATA_BSF) += opus_metadata_bsf.o
OBJS-$(CONFIG_PCM_RECHUNK_BSF) += pcm_rechunk_bsf.o
OBJS-$(CONFIG_PRORES_METADATA_BSF) += prores_metadata_bsf.o
OBJS-$(CONFIG_REMOVE_EXTRADATA_BSF) += remove_extradata_bsf.o
+OBJS-$(CONFIG_SETTS_BSF) += setts_bsf.o
OBJS-$(CONFIG_TEXT2MOVSUB_BSF) += movsub_bsf.o
OBJS-$(CONFIG_TRACE_HEADERS_BSF) += trace_headers_bsf.o
OBJS-$(CONFIG_TRUEHD_CORE_BSF) += truehd_core_bsf.o mlp_parse.o mlp.o
diff --git a/libavcodec/bitstream_filters.c b/libavcodec/bitstream_filters.c
index b26d6a910e..02d33abb18 100644
--- a/libavcodec/bitstream_filters.c
+++ b/libavcodec/bitstream_filters.c
@@ -53,6 +53,7 @@ extern const AVBitStreamFilter ff_opus_metadata_bsf;
extern const AVBitStreamFilter ff_pcm_rechunk_bsf;
extern const AVBitStreamFilter ff_prores_metadata_bsf;
extern const AVBitStreamFilter ff_remove_extradata_bsf;
+extern const AVBitStreamFilter ff_setts_bsf;
extern const AVBitStreamFilter ff_text2movsub_bsf;
extern const AVBitStreamFilter ff_trace_headers_bsf;
extern const AVBitStreamFilter ff_truehd_core_bsf;
diff --git a/libavcodec/setts_bsf.c b/libavcodec/setts_bsf.c
new file mode 100644
index 0000000000..070473ddfa
--- /dev/null
+++ b/libavcodec/setts_bsf.c
@@ -0,0 +1,215 @@
+/*
+ * 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 "avcodec.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_OUTPTS", ///< previous output PTS
+ "PREV_OUTDTS", ///< previous output DTS
+ "PTS", ///< original PTS in the file of the frame
+ "DTS", ///< original DTS in the file of the frame
+ "STARTPTS", ///< PTS at start of movie
+ "STARTDTS", ///< DTS at start of movie
+ NULL
+};
+
+enum var_name {
+ VAR_N,
+ VAR_TS,
+ VAR_POS,
+ VAR_PREV_INPTS,
+ VAR_PREV_INDTS,
+ VAR_PREV_OUTPTS,
+ VAR_PREV_OUTDTS,
+ VAR_PTS,
+ VAR_DTS,
+ VAR_STARTPTS,
+ VAR_STARTDTS,
+ VAR_VARS_NB
+};
+
+typedef struct SetTSContext {
+ const AVClass *class;
+
+ char *ts_str;
+ char *pts_str;
+ char *dts_str;
+
+ int64_t frame_number;
+
+ int64_t start_pts;
+ int64_t start_dts;
+ int64_t prev_inpts;
+ int64_t prev_indts;
+ int64_t prev_outpts;
+ int64_t prev_outdts;
+
+ double var_values[VAR_VARS_NB];
+
+ AVExpr *ts_expr;
+ AVExpr *pts_expr;
+ AVExpr *dts_expr;
+} SetTSContext;
+
+static int setts_init(AVBSFContext *ctx)
+{
+ SetTSContext *s = ctx->priv_data;
+ int ret;
+
+ 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 (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;
+ }
+ }
+
+ s->frame_number= 0;
+ s->start_pts = AV_NOPTS_VALUE;
+ s->start_dts = AV_NOPTS_VALUE;
+ s->prev_inpts = AV_NOPTS_VALUE;
+ s->prev_indts = AV_NOPTS_VALUE;
+ s->prev_outpts = AV_NOPTS_VALUE;
+ s->prev_outdts = AV_NOPTS_VALUE;
+
+ return 0;
+}
+
+static int setts_filter(AVBSFContext *ctx, AVPacket *pkt)
+{
+ SetTSContext *s = ctx->priv_data;
+ int64_t new_ts, new_pts, new_dts;
+ int ret;
+
+ ret = ff_bsf_get_packet_ref(ctx, pkt);
+ if (ret < 0)
+ return ret;
+
+ if (s->start_pts == AV_NOPTS_VALUE)
+ s->start_pts = pkt->pts;
+
+ if (s->start_dts == AV_NOPTS_VALUE)
+ s->start_dts = pkt->dts;
+
+ s->var_values[VAR_N] = s->frame_number++;
+ s->var_values[VAR_TS] = pkt->dts;
+ s->var_values[VAR_POS] = pkt->pos;
+ s->var_values[VAR_PTS] = pkt->pts;
+ s->var_values[VAR_DTS] = pkt->dts;
+ s->var_values[VAR_PREV_INPTS] = s->prev_inpts;
+ s->var_values[VAR_PREV_INDTS] = s->prev_indts;
+ s->var_values[VAR_PREV_OUTPTS] = s->prev_outpts;
+ s->var_values[VAR_PREV_OUTDTS] = s->prev_outdts;
+ s->var_values[VAR_STARTPTS] = s->start_pts;
+ s->var_values[VAR_STARTDTS] = s->start_dts;
+
+ new_ts = llrint(av_expr_eval(s->ts_expr, s->var_values, NULL));
+
+ if (s->pts_str) {
+ s->var_values[VAR_TS] = 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] = pkt->dts;
+ new_dts = llrint(av_expr_eval(s->dts_expr, s->var_values, NULL));
+ } else {
+ new_dts = new_ts;
+ }
+
+ s->var_values[VAR_PREV_INPTS] = pkt->pts;
+ s->var_values[VAR_PREV_INDTS] = pkt->dts;
+ s->var_values[VAR_PREV_OUTPTS] = new_pts;
+ s->var_values[VAR_PREV_OUTDTS] = new_dts;
+
+ pkt->pts = new_pts;
+ pkt->dts = new_dts;
+
+ return ret;
+}
+
+static void setts_close(AVBSFContext *bsf)
+{
+ SetTSContext *s = bsf->priv_data;
+
+ 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;
+}
+
+#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", NULL, OFFSET(ts_str), AV_OPT_TYPE_STRING, {.str="TS"}, 0, 0, FLAGS },
+ { "pts", NULL, OFFSET(pts_str), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, FLAGS },
+ { "dts", NULL, OFFSET(dts_str), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, FLAGS },
+ { NULL },
+};
+
+static const AVClass setts_class = {
+ .class_name = "setts_bsf",
+ .item_name = av_default_item_name,
+ .option = options,
+ .version = LIBAVUTIL_VERSION_INT,
+};
+
+const AVBitStreamFilter ff_setts_bsf = {
+ .name = "setts",
+ .priv_data_size = sizeof(SetTSContext),
+ .priv_class = &setts_class,
+ .init = setts_init,
+ .close = setts_close,
+ .filter = setts_filter,
+};
--
2.17.1
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