FFmpeg
assdec.c
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1 /*
2  * SSA/ASS decoder
3  * Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org>
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include <string.h>
23 
24 #include "avcodec.h"
25 #include "ass.h"
26 #include "codec_internal.h"
27 #include "config_components.h"
28 #include "libavutil/internal.h"
29 #include "libavutil/mem.h"
30 
31 static av_cold int ass_decode_init(AVCodecContext *avctx)
32 {
33  avctx->subtitle_header = av_malloc(avctx->extradata_size + 1);
34  if (!avctx->subtitle_header)
35  return AVERROR(ENOMEM);
36  if (avctx->extradata_size)
37  memcpy(avctx->subtitle_header, avctx->extradata, avctx->extradata_size);
38  avctx->subtitle_header[avctx->extradata_size] = 0;
39  avctx->subtitle_header_size = avctx->extradata_size;
40  return 0;
41 }
42 
43 static int ass_decode_frame(AVCodecContext *avctx, AVSubtitle *sub,
44  int *got_sub_ptr, const AVPacket *avpkt)
45 {
46  if (avpkt->size <= 0)
47  return avpkt->size;
48 
49  sub->rects = av_malloc(sizeof(*sub->rects));
50  if (!sub->rects)
51  return AVERROR(ENOMEM);
52  sub->rects[0] = av_mallocz(sizeof(*sub->rects[0]));
53  if (!sub->rects[0])
54  return AVERROR(ENOMEM);
55  sub->num_rects = 1;
56  sub->rects[0]->type = SUBTITLE_ASS;
57  sub->rects[0]->ass = av_strdup(avpkt->data);
58  if (!sub->rects[0]->ass)
59  return AVERROR(ENOMEM);
60  *got_sub_ptr = 1;
61  return avpkt->size;
62 }
63 
64 #if CONFIG_SSA_DECODER
65 const FFCodec ff_ssa_decoder = {
66  .p.name = "ssa",
67  .p.long_name = NULL_IF_CONFIG_SMALL("ASS (Advanced SubStation Alpha) subtitle"),
68  .p.type = AVMEDIA_TYPE_SUBTITLE,
69  .p.id = AV_CODEC_ID_ASS,
70  .init = ass_decode_init,
71  FF_CODEC_DECODE_SUB_CB(ass_decode_frame),
72  .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
73 };
74 #endif
75 
76 #if CONFIG_ASS_DECODER
77 const FFCodec ff_ass_decoder = {
78  .p.name = "ass",
79  .p.long_name = NULL_IF_CONFIG_SMALL("ASS (Advanced SubStation Alpha) subtitle"),
80  .p.type = AVMEDIA_TYPE_SUBTITLE,
81  .p.id = AV_CODEC_ID_ASS,
82  .init = ass_decode_init,
83  FF_CODEC_DECODE_SUB_CB(ass_decode_frame),
84  .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
85 };
86 #endif
AVSubtitle
Definition: avcodec.h:2306
AVMEDIA_TYPE_SUBTITLE
@ AVMEDIA_TYPE_SUBTITLE
Definition: avutil.h:204
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
sub
static float sub(float src0, float src1)
Definition: dnn_backend_native_layer_mathbinary.c:31
AVPacket::data
uint8_t * data
Definition: packet.h:374
FFCodec
Definition: codec_internal.h:112
AVCodecContext::subtitle_header
uint8_t * subtitle_header
Header containing style information for text subtitles.
Definition: avcodec.h:1706
av_malloc
#define av_malloc(s)
Definition: tableprint_vlc.h:30
SUBTITLE_ASS
@ SUBTITLE_ASS
Formatted text, the ass field must be set by the decoder and is authoritative.
Definition: avcodec.h:2273
AV_CODEC_ID_ASS
@ AV_CODEC_ID_ASS
Definition: codec_id.h:547
FFCodec::p
AVCodec p
The public AVCodec.
Definition: codec_internal.h:116
ass.h
av_cold
#define av_cold
Definition: attributes.h:90
AVCodecContext::extradata_size
int extradata_size
Definition: avcodec.h:491
ff_ass_decoder
const FFCodec ff_ass_decoder
AVCodecContext::subtitle_header_size
int subtitle_header_size
Definition: avcodec.h:1707
ass_decode_frame
static int ass_decode_frame(AVCodecContext *avctx, AVSubtitle *sub, int *got_sub_ptr, const AVPacket *avpkt)
Definition: assdec.c:43
ff_ssa_decoder
const FFCodec ff_ssa_decoder
AVPacket::size
int size
Definition: packet.h:375
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:116
codec_internal.h
AVCodecContext::extradata
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:490
internal.h
FF_CODEC_CAP_INIT_THREADSAFE
#define FF_CODEC_CAP_INIT_THREADSAFE
The codec does not modify any global variables in the init function, allowing to call the init functi...
Definition: codec_internal.h:31
av_mallocz
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:264
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:203
avcodec.h
ass_decode_init
static av_cold int ass_decode_init(AVCodecContext *avctx)
Definition: assdec.c:31
AVCodecContext
main external API structure.
Definition: avcodec.h:389
FF_CODEC_DECODE_SUB_CB
#define FF_CODEC_DECODE_SUB_CB(func)
Definition: codec_internal.h:257
av_strdup
char * av_strdup(const char *s)
Duplicate a string.
Definition: mem.c:280
mem.h
AVPacket
This structure stores compressed data.
Definition: packet.h:351
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