[FFmpeg-cvslog] lavc/pgs_frame_merge_bsf: add bsf to merge PGS segments
John Stebbins
git at videolan.org
Tue May 10 11:24:43 EEST 2022
ffmpeg | branch: master | John Stebbins <jstebbins at jetheaddev.com> | Fri May 8 08:11:24 2020 -0600| [326f9fd01be8b67b2aa155f8f988d274a227e655] | committer: Andreas Rheinhardt
lavc/pgs_frame_merge_bsf: add bsf to merge PGS segments
Required to remux m2ts to mkv
Minor changes and porting to FFBitStreamFilter done by the committer.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=326f9fd01be8b67b2aa155f8f988d274a227e655
---
Changelog | 1 +
doc/bitstream_filters.texi | 8 ++
libavcodec/Makefile | 1 +
libavcodec/bitstream_filters.c | 1 +
libavcodec/pgs_frame_merge_bsf.c | 191 +++++++++++++++++++++++++++++++++++++++
libavcodec/version.h | 2 +-
6 files changed, 203 insertions(+), 1 deletion(-)
diff --git a/Changelog b/Changelog
index 9eca714bbd..4d42a0f681 100644
--- a/Changelog
+++ b/Changelog
@@ -15,6 +15,7 @@ version 5.1:
- colorchart video source filter
- blurdetect filter
- multiply video filter
+- PGS subtitle frame merge bitstream filter
version 5.0:
diff --git a/doc/bitstream_filters.texi b/doc/bitstream_filters.texi
index fc2c71fc12..50c95f035d 100644
--- a/doc/bitstream_filters.texi
+++ b/doc/bitstream_filters.texi
@@ -695,6 +695,14 @@ for NTSC frame rate using the @option{frame_rate} option.
ffmpeg -f lavfi -i sine=r=48000:d=1 -c pcm_s16le -bsf pcm_rechunk=r=30000/1001 -f framecrc -
@end example
+ at section pgs_frame_merge
+
+Merge a sequence of PGS Subtitle segments ending with an "end of display set"
+segment into a single packet.
+
+This is required by some containers that support PGS subtitles
+(muxer @code{matroska}).
+
@section prores_metadata
Modify color property metadata embedded in prores stream.
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 1b60e0e1d4..38425d2f22 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -1196,6 +1196,7 @@ OBJS-$(CONFIG_NOISE_BSF) += noise_bsf.o
OBJS-$(CONFIG_NULL_BSF) += null_bsf.o
OBJS-$(CONFIG_OPUS_METADATA_BSF) += opus_metadata_bsf.o
OBJS-$(CONFIG_PCM_RECHUNK_BSF) += pcm_rechunk_bsf.o
+OBJS-$(CONFIG_PGS_FRAME_MERGE_BSF) += pgs_frame_merge_bsf.o
OBJS-$(CONFIG_PRORES_METADATA_BSF) += prores_metadata_bsf.o
OBJS-$(CONFIG_REMOVE_EXTRADATA_BSF) += remove_extradata_bsf.o av1_parse.o
OBJS-$(CONFIG_SETTS_BSF) += setts_bsf.o
diff --git a/libavcodec/bitstream_filters.c b/libavcodec/bitstream_filters.c
index f117bc0e17..444423ae93 100644
--- a/libavcodec/bitstream_filters.c
+++ b/libavcodec/bitstream_filters.c
@@ -52,6 +52,7 @@ extern const FFBitStreamFilter ff_noise_bsf;
extern const FFBitStreamFilter ff_null_bsf;
extern const FFBitStreamFilter ff_opus_metadata_bsf;
extern const FFBitStreamFilter ff_pcm_rechunk_bsf;
+extern const FFBitStreamFilter ff_pgs_frame_merge_bsf;
extern const FFBitStreamFilter ff_prores_metadata_bsf;
extern const FFBitStreamFilter ff_remove_extradata_bsf;
extern const FFBitStreamFilter ff_setts_bsf;
diff --git a/libavcodec/pgs_frame_merge_bsf.c b/libavcodec/pgs_frame_merge_bsf.c
new file mode 100644
index 0000000000..bcd8945335
--- /dev/null
+++ b/libavcodec/pgs_frame_merge_bsf.c
@@ -0,0 +1,191 @@
+/*
+ * Copyright (c) 2020 John Stebbins <jstebbins.hb at gmail.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
+ */
+
+/**
+ * @file
+ * This bitstream filter merges PGS subtitle packets containing incomplete
+ * set of segments into a single packet
+ *
+ * Packets already containing a complete set of segments will be passed through
+ * unchanged.
+ */
+
+#include "libavutil/attributes.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/log.h"
+#include "bsf.h"
+#include "bsf_internal.h"
+
+enum PGSSegmentType {
+ PALETTE_SEGMENT = 0x14,
+ OBJECT_SEGMENT = 0x15,
+ PRESENTATION_SEGMENT = 0x16,
+ WINDOW_SEGMENT = 0x17,
+ END_DISPLAY_SET_SEGMENT = 0x80,
+};
+
+typedef struct PGSMergeContext {
+ AVPacket *buffer_pkt, *in;
+ int presentation_found;
+ int pkt_flags;
+} PGSMergeContext;
+
+static av_cold void frame_merge_flush(AVBSFContext *bsf)
+{
+ PGSMergeContext *ctx = bsf->priv_data;
+
+ ctx->presentation_found = ctx->pkt_flags = 0;
+ av_packet_unref(ctx->in);
+ av_packet_unref(ctx->buffer_pkt);
+}
+
+static int frame_merge_output(PGSMergeContext *ctx, AVPacket *dst, AVPacket *src)
+{
+ if (!ctx->presentation_found)
+ ctx->pkt_flags |= AV_PKT_FLAG_CORRUPT;
+ ctx->presentation_found = 0;
+ src->flags |= ctx->pkt_flags;
+ ctx->pkt_flags = 0;
+ av_packet_move_ref(dst, src);
+ return 0;
+}
+
+static int frame_merge_filter(AVBSFContext *bsf, AVPacket *out)
+{
+ PGSMergeContext *ctx = bsf->priv_data;
+ AVPacket *in = ctx->in, *pkt = ctx->buffer_pkt;
+ int ret, size, pos, display = 0, presentation = 0;
+ unsigned int i;
+
+ if (!in->data) {
+ ret = ff_bsf_get_packet_ref(bsf, in);
+ if (ret == AVERROR_EOF && pkt->data) {
+ // Output remaining data
+ ctx->pkt_flags |= AV_PKT_FLAG_CORRUPT;
+ return frame_merge_output(ctx, out, pkt);
+ }
+ if (ret < 0)
+ return ret;
+ }
+ if (!in->size) {
+ av_packet_unref(in);
+ return AVERROR(EAGAIN);
+ }
+ in->flags &= ~AV_PKT_FLAG_KEY; // Will be detected in the stream
+
+ // Validate packet data and find display_end segment
+ size = in->size;
+ i = 0;
+ while (i + 3 <= in->size) {
+ uint8_t segment_type = in->data[i];
+ int segment_len = AV_RB16(in->data + i + 1) + 3;
+
+ if (i + segment_len > in->size)
+ break; // Invalid, segments can't span packets
+ if (segment_type == PRESENTATION_SEGMENT && ctx->presentation_found)
+ break; // Invalid, there can be only one
+ if (segment_type == PRESENTATION_SEGMENT) {
+ uint8_t state;
+ if (segment_len < 11)
+ break; // Invalid presentation segment length
+ ctx->presentation_found = presentation = 1;
+ state = in->data[i + 10] & 0xc0;
+ if (state)
+ ctx->pkt_flags |= AV_PKT_FLAG_KEY;
+ else
+ ctx->pkt_flags &= ~AV_PKT_FLAG_KEY;
+ }
+ i += segment_len;
+ if (segment_type == END_DISPLAY_SET_SEGMENT) {
+ size = i;
+ display = 1;
+ break;
+ }
+ }
+ if (display && pkt->size == 0 && size == in->size) // passthrough
+ return frame_merge_output(ctx, out, in);
+ if (!display && i != in->size) {
+ av_log(bsf, AV_LOG_WARNING, "Failed to parse PGS segments.\n");
+ // force output what we have
+ size = in->size;
+ display = 1;
+ ctx->pkt_flags |= AV_PKT_FLAG_CORRUPT;
+ }
+
+ if (presentation) {
+ ret = av_packet_copy_props(pkt, in);
+ if (ret < 0)
+ goto fail;
+ }
+ pos = pkt->size;
+ ret = av_grow_packet(pkt, size);
+ if (ret < 0)
+ goto fail;
+ memcpy(pkt->data + pos, in->data, size);
+
+ if (size == in->size)
+ av_packet_unref(in);
+ else {
+ in->data += size;
+ in->size -= size;
+ }
+
+ if (display)
+ return frame_merge_output(ctx, out, pkt);
+ return AVERROR(EAGAIN);
+
+fail:
+ frame_merge_flush(bsf);
+ return ret;
+}
+
+static av_cold int frame_merge_init(AVBSFContext *bsf)
+{
+ PGSMergeContext *ctx = bsf->priv_data;
+
+ ctx->in = av_packet_alloc();
+ ctx->buffer_pkt = av_packet_alloc();
+ if (!ctx->in || !ctx->buffer_pkt)
+ return AVERROR(ENOMEM);
+
+ return 0;
+}
+
+static av_cold void frame_merge_close(AVBSFContext *bsf)
+{
+ PGSMergeContext *ctx = bsf->priv_data;
+
+ av_packet_free(&ctx->in);
+ av_packet_free(&ctx->buffer_pkt);
+}
+
+static const enum AVCodecID frame_merge_codec_ids[] = {
+ AV_CODEC_ID_HDMV_PGS_SUBTITLE, AV_CODEC_ID_NONE,
+};
+
+const FFBitStreamFilter ff_pgs_frame_merge_bsf = {
+ .p.name = "pgs_frame_merge",
+ .p.codec_ids = frame_merge_codec_ids,
+ .priv_data_size = sizeof(PGSMergeContext),
+ .init = frame_merge_init,
+ .flush = frame_merge_flush,
+ .close = frame_merge_close,
+ .filter = frame_merge_filter,
+};
diff --git a/libavcodec/version.h b/libavcodec/version.h
index 735c8b813c..87b7284a95 100644
--- a/libavcodec/version.h
+++ b/libavcodec/version.h
@@ -29,7 +29,7 @@
#include "version_major.h"
-#define LIBAVCODEC_VERSION_MINOR 27
+#define LIBAVCODEC_VERSION_MINOR 28
#define LIBAVCODEC_VERSION_MICRO 100
#define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
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