From 326f9fd01be8b67b2aa155f8f988d274a227e655 Mon Sep 17 00:00:00 2001 From: John Stebbins Date: Fri, 8 May 2020 08:11:24 -0600 Subject: 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 --- libavcodec/pgs_frame_merge_bsf.c | 191 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 191 insertions(+) create mode 100644 libavcodec/pgs_frame_merge_bsf.c (limited to 'libavcodec/pgs_frame_merge_bsf.c') 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 + * + * 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, +}; -- cgit v1.2.3