mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-12-07 11:13:41 +02:00
d61240f8c9
Up until now, we had a PacketList structure which is actually a PacketListEntry; a proper PacketList did not exist and all the related functions just passed pointers to pointers to the head and tail elements around. All these pointers were actually consecutive elements of their containing structs, i.e. the users already treated them as if they were a struct. So add a proper PacketList struct and rename the current PacketList to PacketListEntry; also make the functions use this structure instead of the pair of pointers. Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
170 lines
5.2 KiB
C
170 lines
5.2 KiB
C
/*
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* MP4, ISMV Muxer TTML helpers
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* Copyright (c) 2021 24i
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "avformat.h"
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#include "avio_internal.h"
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#include "isom.h"
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#include "movenc.h"
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#include "movenc_ttml.h"
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#include "libavcodec/packet_internal.h"
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static const unsigned char empty_ttml_document[] =
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"<tt xml:lang=\"\" xmlns=\"http://www.w3.org/ns/ttml\" />";
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static int mov_init_ttml_writer(MOVTrack *track, AVFormatContext **out_ctx)
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{
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AVStream *movenc_stream = track->st, *ttml_stream = NULL;
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int ret = AVERROR_BUG;
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if ((ret = avformat_alloc_output_context2(out_ctx, NULL,
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"ttml", NULL)) < 0)
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return ret;
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if ((ret = avio_open_dyn_buf(&(*out_ctx)->pb)) < 0)
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return ret;
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if (!(ttml_stream = avformat_new_stream(*out_ctx, NULL))) {
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return AVERROR(ENOMEM);
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}
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if ((ret = avcodec_parameters_copy(ttml_stream->codecpar,
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movenc_stream->codecpar)) < 0)
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return ret;
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ttml_stream->time_base = movenc_stream->time_base;
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return 0;
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}
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static int mov_write_ttml_document_from_queue(AVFormatContext *s,
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AVFormatContext *ttml_ctx,
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MOVTrack *track,
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AVPacket *pkt,
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int64_t *out_start_ts,
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int64_t *out_duration)
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{
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int ret = AVERROR_BUG;
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int64_t start_ts = track->start_dts == AV_NOPTS_VALUE ?
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0 : (track->start_dts + track->track_duration);
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int64_t end_ts = start_ts;
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if ((ret = avformat_write_header(ttml_ctx, NULL)) < 0) {
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return ret;
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}
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while (!avpriv_packet_list_get(&track->squashed_packet_queue, pkt)) {
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end_ts = FFMAX(end_ts, pkt->pts + pkt->duration);
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// in case of the 'dfxp' muxing mode, each written document is offset
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// to its containing sample's beginning.
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if (track->par->codec_tag == MOV_ISMV_TTML_TAG) {
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pkt->dts = pkt->pts = (pkt->pts - start_ts);
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}
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pkt->stream_index = 0;
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av_packet_rescale_ts(pkt, track->st->time_base,
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ttml_ctx->streams[pkt->stream_index]->time_base);
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if ((ret = av_write_frame(ttml_ctx, pkt)) < 0) {
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goto cleanup;
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}
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av_packet_unref(pkt);
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}
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if ((ret = av_write_trailer(ttml_ctx)) < 0)
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goto cleanup;
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*out_start_ts = start_ts;
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*out_duration = end_ts - start_ts;
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ret = 0;
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cleanup:
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return ret;
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}
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int ff_mov_generate_squashed_ttml_packet(AVFormatContext *s,
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MOVTrack *track, AVPacket *pkt)
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{
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AVFormatContext *ttml_ctx = NULL;
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// values for the generated AVPacket
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int64_t start_ts = 0;
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int64_t duration = 0;
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int ret = AVERROR_BUG;
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if ((ret = mov_init_ttml_writer(track, &ttml_ctx)) < 0) {
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av_log(s, AV_LOG_ERROR, "Failed to initialize the TTML writer: %s\n",
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av_err2str(ret));
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goto cleanup;
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}
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if (!track->squashed_packet_queue.head) {
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// empty queue, write minimal empty document with zero duration
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avio_write(ttml_ctx->pb, empty_ttml_document,
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sizeof(empty_ttml_document) - 1);
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start_ts = 0;
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duration = 0;
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goto generate_packet;
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}
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if ((ret = mov_write_ttml_document_from_queue(s, ttml_ctx, track, pkt,
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&start_ts,
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&duration)) < 0) {
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av_log(s, AV_LOG_ERROR,
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"Failed to generate a squashed TTML packet from the packet "
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"queue: %s\n",
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av_err2str(ret));
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goto cleanup;
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}
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generate_packet:
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{
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// Generate an AVPacket from the data written into the dynamic buffer.
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uint8_t *buf = NULL;
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int buf_len = avio_close_dyn_buf(ttml_ctx->pb, &buf);
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ttml_ctx->pb = NULL;
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if ((ret = av_packet_from_data(pkt, buf, buf_len)) < 0) {
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av_log(s, AV_LOG_ERROR,
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"Failed to create a TTML AVPacket from AVIO data: %s\n",
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av_err2str(ret));
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av_freep(&buf);
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goto cleanup;
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}
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pkt->pts = pkt->dts = start_ts;
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pkt->duration = duration;
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pkt->flags |= AV_PKT_FLAG_KEY;
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}
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ret = 0;
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cleanup:
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if (ttml_ctx)
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ffio_free_dyn_buf(&ttml_ctx->pb);
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avformat_free_context(ttml_ctx);
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return ret;
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}
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