[FFmpeg-devel] [PATCH 02/11] lavf: add internal demuxer helpers for subtitles.
Stefano Sabatini
stefasab at gmail.com
Sat Jun 23 00:30:53 CEST 2012
On date Friday 2012-06-22 22:43:57 +0200, Clément Bœsch encoded:
> ---
> libavformat/Makefile | 1 +
> libavformat/subtitles.c | 101 ++++++++++++++++++++++++++++++++++++++++++++++++
> libavformat/subtitles.h | 61 +++++++++++++++++++++++++++++
> 3 files changed, 163 insertions(+)
> create mode 100644 libavformat/subtitles.c
> create mode 100644 libavformat/subtitles.h
>
> diff --git a/libavformat/Makefile b/libavformat/Makefile
> index 9032654..0060296 100644
> --- a/libavformat/Makefile
> +++ b/libavformat/Makefile
> @@ -19,6 +19,7 @@ OBJS = allformats.o \
> riff.o \
> sdp.o \
> seek.o \
> + subtitles.o \
> utils.o \
>
> OBJS-$(CONFIG_NETWORK) += network.o
> diff --git a/libavformat/subtitles.c b/libavformat/subtitles.c
> new file mode 100644
> index 0000000..ce6cc35
> --- /dev/null
> +++ b/libavformat/subtitles.c
> @@ -0,0 +1,101 @@
> +/*
> + * Copyright (c) 2012 Clément Bœsch
> + *
> + * 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
> + */
> +
> +#include "avformat.h"
> +#include "subtitles.h"
> +
> +AVPacket *ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q,
> + const uint8_t *event, int len, int merge)
> +{
> + AVPacket *subs, *sub;
> +
> + if (merge && q->nsub > 0) {
> + /* merge with previous event */
> +
> + int old_len;
> + sub = &q->subs[q->nsub - 1];
> + old_len = sub->size;
> + if (av_grow_packet(sub, len) < 0)
> + return NULL;
> + memcpy(sub->data + old_len, event, len);
> + } else {
> + /* new event */
> +
> + if (q->nsub >= INT_MAX/sizeof(*q->subs) - 1)
> + return NULL;
> + subs = av_fast_realloc(q->subs, &q->allocated_size,
> + (q->nsub + 1) * sizeof(*q->subs));
> + if (!subs)
> + return NULL;
> + q->subs = subs;
> + sub = &subs[q->nsub++];
> + if (av_new_packet(sub, len) < 0)
> + return NULL;
> + sub->destruct = NULL;
> + sub->flags |= AV_PKT_FLAG_KEY;
> + sub->pts = sub->dts = 0;
> + memcpy(sub->data, event, len);
> + }
> + return sub;
> +}
> +
> +static int cmp_pkt_sub(const void *a, const void *b)
> +{
> + const AVPacket *s1 = a;
> + const AVPacket *s2 = b;
> + if (s1->pts == s2->pts) {
> + if (s1->pos == s2->pos)
> + return 0;
> + return s1->pos > s2->pos ? 1 : -1;
> + }
> + return s1->pts > s2->pts ? 1 : -1;
> +}
> +
> +void ff_subtitles_queue_finalize(FFDemuxSubtitlesQueue *q)
> +{
> + int i;
> +
> + qsort(q->subs, q->nsub, sizeof(*q->subs), cmp_pkt_sub);
> + for (i = 0; i < q->nsub; i++)
> + if (q->subs[i].duration == -1 && i < q->nsub - 1)
> + q->subs[i].duration = q->subs[i + 1].pts - q->subs[i].pts;
> +}
> +
> +int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt)
> +{
> + AVPacket *sub = q->subs + q->current_sub;
> +
> + if (q->current_sub == q->nsub)
> + return AVERROR_EOF;
I'd consider safer to set q to NULL in that case, rather than point to
foo data.
> + *pkt = *sub;
> + pkt->dts = pkt->pts;
> + q->current_sub++;
> + return 0;
> +}
> +
> +void ff_subtitles_queue_free(FFDemuxSubtitlesQueue *q)
> +{
> + int i;
> +
> + for (i = 0; i < q->nsub; i++)
> + av_destruct_packet(&q->subs[i]);
> + av_freep(&q->subs);
> + q->nsub = q->allocated_size = q->current_sub = 0;
> +}
> diff --git a/libavformat/subtitles.h b/libavformat/subtitles.h
> new file mode 100644
> index 0000000..3373027
> --- /dev/null
> +++ b/libavformat/subtitles.h
> @@ -0,0 +1,61 @@
> +/*
> + * Copyright (c) 2012 Clément Bœsch
> + *
> + * 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
> + */
> +
> +#ifndef AVFORMAT_SUBTITLES_H
> +#define AVFORMAT_SUBTITLES_H
> +
> +#include <stdint.h>
> +#include "avformat.h"
> +
> +typedef struct {
> + AVPacket *subs; ///< array of subtitles packets
> + int nsub; ///< number of subtitles packets
nit++: nb_subs?
> + int allocated_size; ///< allocated size for subs
> + int current_sub; ///< current position for the read packet callback
nit++: current_sub_idx?
> +} FFDemuxSubtitlesQueue;
> +
> +/**
> + * Insert a new subtitle event
Nit: here and below, missing terminating dots.
> + *
> + * @param event the subtitle line, may not be zero terminated
> + * @param len the length of the event
length is always a bit ambiguous when dealing with string (it is a
buffer size or a length in the sense of strlen()?).
> + * @param merge set to 1 if the current event should be concatenated with the
> + * previous one instead of adding a new entry, 0 otherwise
> + */
> +AVPacket *ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q,
> + const uint8_t *event, int len, int merge);
> +
> +/**
> + * Set missing durations and sort subtitles by PTS, and then byte position
> + */
> +void ff_subtitles_queue_finalize(FFDemuxSubtitlesQueue *q);
> +
> +/**
> + * Generic read_packet() callback for subtitles demuxers using this queue
> + * system
> + */
> +int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt);
> +
> +/**
> + * Remove and destroy all the subtitles packets
> + */
> +void ff_subtitles_queue_free(FFDemuxSubtitlesQueue *q);
This is slightly confusing, since the queue structure itself is not
freed (maybe "clean" may be less ambiguous).
> +
> +#endif /* AVFORMAT_SUBTITLES_H */
> --
> 1.7.11
>
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