FFmpeg
xsubenc.c
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1 /*
2  * DivX (XSUB) subtitle encoder
3  * Copyright (c) 2005 DivX, Inc.
4  * Copyright (c) 2009 Bjorn Axelsson
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 #include "avcodec.h"
24 #include "bytestream.h"
25 #include "put_bits.h"
26 
27 /**
28  * Number of pixels to pad left and right.
29  *
30  * The official encoder pads the subtitles with two pixels on either side,
31  * but until we find out why, we won't do it (we will pad to have width
32  * divisible by 2 though).
33  */
34 #define PADDING 0
35 #define PADDING_COLOR 0
36 
37 /**
38  * Encode a single color run. At most 16 bits will be used.
39  * @param len length of the run, values > 255 mean "until end of line", may not be < 0.
40  * @param color color to encode, only the lowest two bits are used and all others must be 0.
41  */
42 static void put_xsub_rle(PutBitContext *pb, int len, int color)
43 {
44  if (len <= 255)
45  put_bits(pb, 2 + ((ff_log2_tab[len] >> 1) << 2), len);
46  else
47  put_bits(pb, 14, 0);
48  put_bits(pb, 2, color);
49 }
50 
51 /**
52  * Encode a 4-color bitmap with XSUB rle.
53  *
54  * The encoded bitmap may be wider than the source bitmap due to padding.
55  */
56 static int xsub_encode_rle(PutBitContext *pb, const uint8_t *bitmap,
57  int linesize, int w, int h)
58 {
59  int x0, x1, y, len, color = PADDING_COLOR;
60 
61  for (y = 0; y < h; y++) {
62  x0 = 0;
63  while (x0 < w) {
64  // Make sure we have enough room for at least one run and padding
65  if (pb->size_in_bits - put_bits_count(pb) < 7*8)
67 
68  x1 = x0;
69  color = bitmap[x1++] & 3;
70  while (x1 < w && (bitmap[x1] & 3) == color)
71  x1++;
72  len = x1 - x0;
73  if (PADDING && x0 == 0) {
74  if (color == PADDING_COLOR) {
75  len += PADDING;
76  x0 -= PADDING;
77  } else
79  }
80 
81  // Run can't be longer than 255, unless it is the rest of a row
82  if (x1 == w && color == PADDING_COLOR) {
83  len += PADDING + (w&1);
84  } else
85  len = FFMIN(len, 255);
86  put_xsub_rle(pb, len, color);
87 
88  x0 += len;
89  }
90  if (color != PADDING_COLOR && (PADDING + (w&1)))
91  put_xsub_rle(pb, PADDING + (w&1), PADDING_COLOR);
92 
93  align_put_bits(pb);
94 
95  bitmap += linesize;
96  }
97 
98  return 0;
99 }
100 
101 static int make_tc(uint64_t ms, int *tc)
102 {
103  static const int tc_divs[3] = { 1000, 60, 60 };
104  int i;
105  for (i=0; i<3; i++) {
106  tc[i] = ms % tc_divs[i];
107  ms /= tc_divs[i];
108  }
109  tc[3] = ms;
110  return ms > 99;
111 }
112 
113 static int xsub_encode(AVCodecContext *avctx, unsigned char *buf,
114  int bufsize, const AVSubtitle *h)
115 {
116  uint64_t startTime = h->pts / 1000; // FIXME: need better solution...
117  uint64_t endTime = startTime + h->end_display_time - h->start_display_time;
118  int start_tc[4], end_tc[4];
119  uint8_t *hdr = buf + 27; // Point behind the timestamp
120  uint8_t *rlelenptr;
121  uint16_t width, height;
122  int i;
123  PutBitContext pb;
124 
125  if (bufsize < 27 + 7*2 + 4*3) {
126  av_log(avctx, AV_LOG_ERROR, "Buffer too small for XSUB header.\n");
128  }
129 
130  // TODO: support multiple rects
131  if (h->num_rects != 1)
132  av_log(avctx, AV_LOG_WARNING, "Only single rects supported (%d in subtitle.)\n", h->num_rects);
133 
134 #if FF_API_AVPICTURE
136  if (!h->rects[0]->data[0]) {
137  AVSubtitleRect *rect = h->rects[0];
138  int j;
139  for (j = 0; j < 4; j++) {
140  rect->data[j] = rect->pict.data[j];
141  rect->linesize[j] = rect->pict.linesize[j];
142  }
143  }
145 #endif
146 
147  // TODO: render text-based subtitles into bitmaps
148  if (!h->rects[0]->data[0] || !h->rects[0]->data[1]) {
149  av_log(avctx, AV_LOG_WARNING, "No subtitle bitmap available.\n");
150  return AVERROR(EINVAL);
151  }
152 
153  // TODO: color reduction, similar to dvdsub encoder
154  if (h->rects[0]->nb_colors > 4)
155  av_log(avctx, AV_LOG_WARNING, "No more than 4 subtitle colors supported (%d found.)\n", h->rects[0]->nb_colors);
156 
157  // TODO: Palette swapping if color zero is not transparent
158  if (((uint32_t *)h->rects[0]->data[1])[0] & 0xff000000)
159  av_log(avctx, AV_LOG_WARNING, "Color index 0 is not transparent. Transparency will be messed up.\n");
160 
161  if (make_tc(startTime, start_tc) || make_tc(endTime, end_tc)) {
162  av_log(avctx, AV_LOG_WARNING, "Time code >= 100 hours.\n");
163  return AVERROR(EINVAL);
164  }
165 
166  snprintf(buf, 28,
167  "[%02d:%02d:%02d.%03d-%02d:%02d:%02d.%03d]",
168  start_tc[3], start_tc[2], start_tc[1], start_tc[0],
169  end_tc[3], end_tc[2], end_tc[1], end_tc[0]);
170 
171  // Width and height must probably be multiples of 2.
172  // 2 pixels required on either side of subtitle.
173  // Possibly due to limitations of hardware renderers.
174  // TODO: check if the bitmap is already padded
175  width = FFALIGN(h->rects[0]->w, 2) + PADDING * 2;
176  height = FFALIGN(h->rects[0]->h, 2);
177 
178  bytestream_put_le16(&hdr, width);
179  bytestream_put_le16(&hdr, height);
180  bytestream_put_le16(&hdr, h->rects[0]->x);
181  bytestream_put_le16(&hdr, h->rects[0]->y);
182  bytestream_put_le16(&hdr, h->rects[0]->x + width -1);
183  bytestream_put_le16(&hdr, h->rects[0]->y + height -1);
184 
185  rlelenptr = hdr; // Will store length of first field here later.
186  hdr+=2;
187 
188  // Palette
189  for (i=0; i<4; i++)
190  bytestream_put_be24(&hdr, ((uint32_t *)h->rects[0]->data[1])[i]);
191 
192  // Bitmap
193  // RLE buffer. Reserve 2 bytes for possible padding after the last row.
194  init_put_bits(&pb, hdr, bufsize - (hdr - buf) - 2);
195  if (xsub_encode_rle(&pb, h->rects[0]->data[0],
196  h->rects[0]->linesize[0] * 2,
197  h->rects[0]->w, (h->rects[0]->h + 1) >> 1))
199  bytestream_put_le16(&rlelenptr, put_bits_count(&pb) >> 3); // Length of first field
200 
201  if (xsub_encode_rle(&pb, h->rects[0]->data[0] + h->rects[0]->linesize[0],
202  h->rects[0]->linesize[0] * 2,
203  h->rects[0]->w, h->rects[0]->h >> 1))
205 
206  // Enforce total height to be a multiple of 2
207  if (h->rects[0]->h & 1) {
208  put_xsub_rle(&pb, h->rects[0]->w, PADDING_COLOR);
209  }
210 
211  flush_put_bits(&pb);
212 
213  return hdr - buf + put_bits_count(&pb)/8;
214 }
215 
217 {
218  if (!avctx->codec_tag)
219  avctx->codec_tag = MKTAG('D','X','S','B');
220 
221  avctx->bits_per_coded_sample = 4;
222 
223  return 0;
224 }
225 
227  .name = "xsub",
228  .long_name = NULL_IF_CONFIG_SMALL("DivX subtitles (XSUB)"),
229  .type = AVMEDIA_TYPE_SUBTITLE,
230  .id = AV_CODEC_ID_XSUB,
231  .init = xsub_encoder_init,
232  .encode_sub = xsub_encode,
233 };
static void align_put_bits(PutBitContext *s)
Pad the bitstream with zeros up to the next byte boundary.
Definition: put_bits.h:393
#define PADDING
Number of pixels to pad left and right.
Definition: xsubenc.c:34
static void put_xsub_rle(PutBitContext *pb, int len, int color)
Encode a single color run.
Definition: xsubenc.c:42
int x
top left corner of pict, undefined when pict is not set
Definition: avcodec.h:2660
static void put_bits(Jpeg2000EncoderContext *s, int val, int n)
put n times val bit
Definition: j2kenc.c:218
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:200
int nb_colors
number of colors in pict, undefined when pict is not set
Definition: avcodec.h:2664
#define tc
Definition: regdef.h:69
unsigned num_rects
Definition: avcodec.h:2698
AVCodec.
Definition: codec.h:190
attribute_deprecated AVPicture pict
Definition: avcodec.h:2671
AVSubtitleRect ** rects
Definition: avcodec.h:2699
int w
width of pict, undefined when pict is not set
Definition: avcodec.h:2662
static int make_tc(uint64_t ms, int *tc)
Definition: xsubenc.c:101
uint8_t
#define av_cold
Definition: attributes.h:88
attribute_deprecated int linesize[AV_NUM_DATA_POINTERS]
number of bytes per line
Definition: avcodec.h:2631
#define height
int h
height of pict, undefined when pict is not set
Definition: avcodec.h:2663
int bits_per_coded_sample
bits per sample/pixel from the demuxer (needed for huffyuv).
Definition: avcodec.h:1750
#define FFALIGN(x, a)
Definition: macros.h:48
#define av_log(a,...)
int size_in_bits
Definition: put_bits.h:55
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:194
int y
top left corner of pict, undefined when pict is not set
Definition: avcodec.h:2661
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:153
static int xsub_encode(AVCodecContext *avctx, unsigned char *buf, int bufsize, const AVSubtitle *h)
Definition: xsubenc.c:113
const char * name
Name of the codec implementation.
Definition: codec.h:197
static int xsub_encode_rle(PutBitContext *pb, const uint8_t *bitmap, int linesize, int w, int h)
Encode a 4-color bitmap with XSUB rle.
Definition: xsubenc.c:56
static int put_bits_count(PutBitContext *s)
Definition: put_bits.h:83
uint32_t end_display_time
Definition: avcodec.h:2697
int64_t pts
Same as packet pts, in AV_TIME_BASE.
Definition: avcodec.h:2700
int linesize[4]
Definition: avcodec.h:2678
#define FFMIN(a, b)
Definition: common.h:96
#define AVERROR_BUFFER_TOO_SMALL
Buffer too small.
Definition: error.h:51
#define width
uint8_t w
Definition: llviddspenc.c:38
attribute_deprecated uint8_t * data[AV_NUM_DATA_POINTERS]
pointers to the image data planes
Definition: avcodec.h:2629
AVCodec ff_xsub_encoder
Definition: xsubenc.c:226
uint8_t * data[4]
data+linesize for the bitmap of this subtitle.
Definition: avcodec.h:2677
const uint8_t ff_log2_tab[256]
Definition: log2_tab.c:23
Libavcodec external API header.
main external API structure.
Definition: avcodec.h:526
unsigned int codec_tag
fourcc (LSB first, so "ABCD" -> (&#39;D&#39;<<24) + (&#39;C&#39;<<16) + (&#39;B&#39;<<8) + &#39;A&#39;).
Definition: avcodec.h:551
Definition: f_ebur128.c:91
#define PADDING_COLOR
Definition: xsubenc.c:35
#define snprintf
Definition: snprintf.h:34
static av_cold int xsub_encoder_init(AVCodecContext *avctx)
Definition: xsubenc.c:216
#define FF_DISABLE_DEPRECATION_WARNINGS
Definition: internal.h:84
static void flush_put_bits(PutBitContext *s)
Pad the end of the output stream with zeros.
Definition: put_bits.h:117
uint32_t start_display_time
Definition: avcodec.h:2696
static void init_put_bits(PutBitContext *s, uint8_t *buffer, int buffer_size)
Initialize the PutBitContext s.
Definition: put_bits.h:64
#define FF_ENABLE_DEPRECATION_WARNINGS
Definition: internal.h:85
int len
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
#define MKTAG(a, b, c, d)
Definition: common.h:405
int i
Definition: input.c:407
bitstream writer API