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1 /*
2  * TDSC decoder
3  * Copyright (C) 2015 Vittorio Giovara <vittorio.giovara@gmail.com>
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 /**
23  * @file
24  * TDSC decoder
25  *
26  * Fourcc: TSDC
27  *
28  * TDSC is very simple. It codes picture by tiles, storing them in raw BGR24
29  * format or compressing them in JPEG. Frames can be full pictures or just
30  * updates to the previous frame. Cursor is found in its own frame or at the
31  * bottom of the picture. Every frame is then packed with zlib.
32  *
33  * Supports: BGR24
34  */
35 
36 #include <stdint.h>
37 #include <zlib.h>
38 
39 #include "libavutil/imgutils.h"
40 
41 #include "avcodec.h"
42 #include "bytestream.h"
43 #include "codec_internal.h"
44 #include "internal.h"
45 
46 #define BITMAPINFOHEADER_SIZE 0x28
47 #define TDSF_HEADER_SIZE      0x56
48 #define TDSB_HEADER_SIZE      0x08
49 
50 typedef struct TDSCContext {
51     AVCodecContext *jpeg_avctx;   // wrapper context for MJPEG
52 
53     int width, height;
54     GetByteContext gbc;
55 
56     AVFrame *refframe;          // full decoded frame (without cursor)
57     AVPacket *jpkt;             // encoded JPEG tile
58     AVFrame *jpgframe;          // decoded JPEG tile
59     uint8_t *tilebuffer;        // buffer containing tile data
60 
61     /* zlib interaction */
62     uint8_t *deflatebuffer;
63     uLongf deflatelen;
64 
65     /* All that is cursor */
66     uint8_t    *cursor;
67     int        cursor_stride;
68     int        cursor_w, cursor_h, cursor_x, cursor_y;
69     int        cursor_hot_x, cursor_hot_y;
70 } TDSCContext;
71 
72 /* 1 byte bits, 1 byte planes, 2 bytes format (probably) */
73 enum TDSCCursorFormat {
74     CUR_FMT_MONO = 0x01010004,
75     CUR_FMT_BGRA = 0x20010004,
76     CUR_FMT_RGBA = 0x20010008,
77 };
78 
tdsc_close(AVCodecContext * avctx)79 static av_cold int tdsc_close(AVCodecContext *avctx)
80 {
81     TDSCContext *ctx = avctx->priv_data;
82 
83     av_frame_free(&ctx->refframe);
84     av_frame_free(&ctx->jpgframe);
85     av_packet_free(&ctx->jpkt);
86     av_freep(&ctx->deflatebuffer);
87     av_freep(&ctx->tilebuffer);
88     av_freep(&ctx->cursor);
89     avcodec_free_context(&ctx->jpeg_avctx);
90 
91     return 0;
92 }
93 
tdsc_init(AVCodecContext * avctx)94 static av_cold int tdsc_init(AVCodecContext *avctx)
95 {
96     TDSCContext *ctx = avctx->priv_data;
97     const AVCodec *codec;
98     int ret;
99 
100     avctx->pix_fmt = AV_PIX_FMT_BGR24;
101 
102     /* These needs to be set to estimate buffer and frame size */
103     if (!(avctx->width && avctx->height)) {
104         av_log(avctx, AV_LOG_ERROR, "Video size not set.\n");
105         return AVERROR_INVALIDDATA;
106     }
107 
108     /* This value should be large enough for a RAW-only frame plus headers */
109     ctx->deflatelen = avctx->width * avctx->height * (3 + 1);
110     ret = av_reallocp(&ctx->deflatebuffer, ctx->deflatelen);
111     if (ret < 0)
112         return ret;
113 
114     /* Allocate reference and JPEG frame */
115     ctx->refframe = av_frame_alloc();
116     ctx->jpgframe = av_frame_alloc();
117     ctx->jpkt     = av_packet_alloc();
118     if (!ctx->refframe || !ctx->jpgframe || !ctx->jpkt)
119         return AVERROR(ENOMEM);
120 
121     /* Prepare everything needed for JPEG decoding */
122     codec = avcodec_find_decoder(AV_CODEC_ID_MJPEG);
123     if (!codec)
124         return AVERROR_BUG;
125     ctx->jpeg_avctx = avcodec_alloc_context3(codec);
126     if (!ctx->jpeg_avctx)
127         return AVERROR(ENOMEM);
128     ctx->jpeg_avctx->flags = avctx->flags;
129     ctx->jpeg_avctx->flags2 = avctx->flags2;
130     ctx->jpeg_avctx->dct_algo = avctx->dct_algo;
131     ctx->jpeg_avctx->idct_algo = avctx->idct_algo;
132     ret = avcodec_open2(ctx->jpeg_avctx, codec, NULL);
133     if (ret < 0)
134         return ret;
135 
136     /* Set the output pixel format on the reference frame */
137     ctx->refframe->format = avctx->pix_fmt;
138 
139     return 0;
140 }
141 
142 #define APPLY_ALPHA(src, new, alpha) \
143     src = (src * (256 - alpha) + new * alpha) >> 8
144 
145 /* Paint a region over a buffer, without drawing out of its bounds. */
tdsc_paint_cursor(AVCodecContext * avctx,uint8_t * dst,int stride)146 static void tdsc_paint_cursor(AVCodecContext *avctx, uint8_t *dst, int stride)
147 {
148     TDSCContext *ctx = avctx->priv_data;
149     const uint8_t *cursor = ctx->cursor;
150     int x = ctx->cursor_x - ctx->cursor_hot_x;
151     int y = ctx->cursor_y - ctx->cursor_hot_y;
152     int w = ctx->cursor_w;
153     int h = ctx->cursor_h;
154     int i, j;
155 
156     if (!ctx->cursor)
157         return;
158 
159     if (x + w > ctx->width)
160         w = ctx->width - x;
161     if (y + h > ctx->height)
162         h = ctx->height - y;
163     if (x < 0) {
164         w      +=  x;
165         cursor += -x * 4;
166     } else {
167         dst    +=  x * 3;
168     }
169     if (y < 0) {
170         h      +=  y;
171         cursor += -y * ctx->cursor_stride;
172     } else {
173         dst    +=  y * stride;
174     }
175     if (w < 0 || h < 0)
176         return;
177 
178     for (j = 0; j < h; j++) {
179         for (i = 0; i < w; i++) {
180             uint8_t alpha = cursor[i * 4];
181             APPLY_ALPHA(dst[i * 3 + 0], cursor[i * 4 + 1], alpha);
182             APPLY_ALPHA(dst[i * 3 + 1], cursor[i * 4 + 2], alpha);
183             APPLY_ALPHA(dst[i * 3 + 2], cursor[i * 4 + 3], alpha);
184         }
185         dst    += stride;
186         cursor += ctx->cursor_stride;
187     }
188 }
189 
190 /* Load cursor data and store it in ABGR mode. */
tdsc_load_cursor(AVCodecContext * avctx)191 static int tdsc_load_cursor(AVCodecContext *avctx)
192 {
193     TDSCContext *ctx  = avctx->priv_data;
194     int i, j, k, ret, cursor_fmt;
195     uint8_t *dst;
196 
197     ctx->cursor_hot_x = bytestream2_get_le16(&ctx->gbc);
198     ctx->cursor_hot_y = bytestream2_get_le16(&ctx->gbc);
199     ctx->cursor_w     = bytestream2_get_le16(&ctx->gbc);
200     ctx->cursor_h     = bytestream2_get_le16(&ctx->gbc);
201 
202     ctx->cursor_stride = FFALIGN(ctx->cursor_w, 32) * 4;
203     cursor_fmt = bytestream2_get_le32(&ctx->gbc);
204 
205     if (ctx->cursor_x >= avctx->width || ctx->cursor_y >= avctx->height) {
206         av_log(avctx, AV_LOG_ERROR,
207                "Invalid cursor position (%d.%d outside %dx%d).\n",
208                ctx->cursor_x, ctx->cursor_y, avctx->width, avctx->height);
209         return AVERROR_INVALIDDATA;
210     }
211     if (ctx->cursor_w < 1 || ctx->cursor_w > 256 ||
212         ctx->cursor_h < 1 || ctx->cursor_h > 256) {
213         av_log(avctx, AV_LOG_ERROR,
214                "Invalid cursor dimensions %dx%d.\n",
215                ctx->cursor_w, ctx->cursor_h);
216         return AVERROR_INVALIDDATA;
217     }
218     if (ctx->cursor_hot_x > ctx->cursor_w ||
219         ctx->cursor_hot_y > ctx->cursor_h) {
220         av_log(avctx, AV_LOG_WARNING, "Invalid hotspot position %d.%d.\n",
221                ctx->cursor_hot_x, ctx->cursor_hot_y);
222         ctx->cursor_hot_x = FFMIN(ctx->cursor_hot_x, ctx->cursor_w - 1);
223         ctx->cursor_hot_y = FFMIN(ctx->cursor_hot_y, ctx->cursor_h - 1);
224     }
225 
226     ret = av_reallocp(&ctx->cursor, ctx->cursor_stride * ctx->cursor_h);
227     if (ret < 0) {
228         av_log(avctx, AV_LOG_ERROR, "Cannot allocate cursor buffer.\n");
229         return ret;
230     }
231 
232     dst = ctx->cursor;
233     /* here data is packed in BE */
234     switch (cursor_fmt) {
235     case CUR_FMT_MONO:
236         for (j = 0; j < ctx->cursor_h; j++) {
237             for (i = 0; i < ctx->cursor_w; i += 32) {
238                 uint32_t bits = bytestream2_get_be32(&ctx->gbc);
239                 for (k = 0; k < 32; k++) {
240                     dst[0] = !!(bits & 0x80000000);
241                     dst   += 4;
242                     bits <<= 1;
243                 }
244             }
245             dst += ctx->cursor_stride - ctx->cursor_w * 4;
246         }
247 
248         dst = ctx->cursor;
249         for (j = 0; j < ctx->cursor_h; j++) {
250             for (i = 0; i < ctx->cursor_w; i += 32) {
251                 uint32_t bits = bytestream2_get_be32(&ctx->gbc);
252                 for (k = 0; k < 32; k++) {
253                     int mask_bit = !!(bits & 0x80000000);
254                     switch (dst[0] * 2 + mask_bit) {
255                     case 0:
256                         dst[0] = 0xFF;
257                         dst[1] = 0x00;
258                         dst[2] = 0x00;
259                         dst[3] = 0x00;
260                         break;
261                     case 1:
262                         dst[0] = 0xFF;
263                         dst[1] = 0xFF;
264                         dst[2] = 0xFF;
265                         dst[3] = 0xFF;
266                         break;
267                     default:
268                         dst[0] = 0x00;
269                         dst[1] = 0x00;
270                         dst[2] = 0x00;
271                         dst[3] = 0x00;
272                     }
273                     dst   += 4;
274                     bits <<= 1;
275                 }
276             }
277             dst += ctx->cursor_stride - ctx->cursor_w * 4;
278         }
279         break;
280     case CUR_FMT_BGRA:
281     case CUR_FMT_RGBA:
282         /* Skip monochrome version of the cursor */
283         bytestream2_skip(&ctx->gbc,
284                          ctx->cursor_h * (FFALIGN(ctx->cursor_w, 32) >> 3));
285         if (cursor_fmt & 8) { // RGBA -> ABGR
286             for (j = 0; j < ctx->cursor_h; j++) {
287                 for (i = 0; i < ctx->cursor_w; i++) {
288                     int val = bytestream2_get_be32(&ctx->gbc);
289                     *dst++ = val >> 24;
290                     *dst++ = val >> 16;
291                     *dst++ = val >>  8;
292                     *dst++ = val >>  0;
293                 }
294                 dst += ctx->cursor_stride - ctx->cursor_w * 4;
295             }
296         } else { // BGRA -> ABGR
297             for (j = 0; j < ctx->cursor_h; j++) {
298                 for (i = 0; i < ctx->cursor_w; i++) {
299                     int val = bytestream2_get_be32(&ctx->gbc);
300                     *dst++ = val >>  0;
301                     *dst++ = val >> 24;
302                     *dst++ = val >> 16;
303                     *dst++ = val >>  8;
304                 }
305                 dst += ctx->cursor_stride - ctx->cursor_w * 4;
306             }
307         }
308         break;
309     default:
310         avpriv_request_sample(avctx, "Cursor format %08x", cursor_fmt);
311         return AVERROR_PATCHWELCOME;
312     }
313 
314     return 0;
315 }
316 
317 /* Convert a single YUV pixel to RGB. */
tdsc_yuv2rgb(uint8_t * out,int Y,int U,int V)318 static inline void tdsc_yuv2rgb(uint8_t *out, int Y, int U, int V)
319 {
320     out[0] = av_clip_uint8(Y + (             91881 * V + 32768 >> 16));
321     out[1] = av_clip_uint8(Y + (-22554 * U - 46802 * V + 32768 >> 16));
322     out[2] = av_clip_uint8(Y + (116130 * U             + 32768 >> 16));
323 }
324 
325 /* Convert a YUV420 buffer to a RGB buffer. */
tdsc_blit(uint8_t * dst,int dst_stride,const uint8_t * srcy,int srcy_stride,const uint8_t * srcu,const uint8_t * srcv,int srcuv_stride,int width,int height)326 static av_always_inline void tdsc_blit(uint8_t *dst, int dst_stride,
327                                        const uint8_t *srcy, int srcy_stride,
328                                        const uint8_t *srcu, const uint8_t *srcv,
329                                        int srcuv_stride, int width, int height)
330 {
331     int col, line;
332     for (line = 0; line < height; line++) {
333         for (col = 0; col < width; col++)
334             tdsc_yuv2rgb(dst + col * 3, srcy[col],
335                          srcu[col >> 1] - 128, srcv[col >> 1] - 128);
336 
337         dst  +=   dst_stride;
338         srcy +=  srcy_stride;
339         srcu += srcuv_stride * (line & 1);
340         srcv += srcuv_stride * (line & 1);
341     }
342 }
343 
344 /* Invoke the MJPEG decoder to decode the tile. */
tdsc_decode_jpeg_tile(AVCodecContext * avctx,int tile_size,int x,int y,int w,int h)345 static int tdsc_decode_jpeg_tile(AVCodecContext *avctx, int tile_size,
346                                  int x, int y, int w, int h)
347 {
348     TDSCContext *ctx = avctx->priv_data;
349     int ret;
350 
351     /* Prepare a packet and send to the MJPEG decoder */
352     av_packet_unref(ctx->jpkt);
353     ctx->jpkt->data = ctx->tilebuffer;
354     ctx->jpkt->size = tile_size;
355 
356     ret = avcodec_send_packet(ctx->jpeg_avctx, ctx->jpkt);
357     if (ret < 0) {
358         av_log(avctx, AV_LOG_ERROR, "Error submitting a packet for decoding\n");
359         return ret;
360     }
361 
362     ret = avcodec_receive_frame(ctx->jpeg_avctx, ctx->jpgframe);
363     if (ret < 0 || ctx->jpgframe->format != AV_PIX_FMT_YUVJ420P) {
364         av_log(avctx, AV_LOG_ERROR,
365                "JPEG decoding error (%d).\n", ret);
366 
367         /* Normally skip, error if explode */
368         if (avctx->err_recognition & AV_EF_EXPLODE)
369             return AVERROR_INVALIDDATA;
370         else
371             return 0;
372     }
373 
374     /* Let's paint onto the buffer */
375     tdsc_blit(ctx->refframe->data[0] + x * 3 + ctx->refframe->linesize[0] * y,
376               ctx->refframe->linesize[0],
377               ctx->jpgframe->data[0], ctx->jpgframe->linesize[0],
378               ctx->jpgframe->data[1], ctx->jpgframe->data[2],
379               ctx->jpgframe->linesize[1], w, h);
380 
381     av_frame_unref(ctx->jpgframe);
382 
383     return 0;
384 }
385 
386 /* Parse frame and either copy data or decode JPEG. */
tdsc_decode_tiles(AVCodecContext * avctx,int number_tiles)387 static int tdsc_decode_tiles(AVCodecContext *avctx, int number_tiles)
388 {
389     TDSCContext *ctx = avctx->priv_data;
390     int i;
391 
392     /* Iterate over the number of tiles */
393     for (i = 0; i < number_tiles; i++) {
394         int tile_size;
395         int tile_mode;
396         int x, y, x2, y2, w, h;
397         int ret;
398 
399         if (bytestream2_get_bytes_left(&ctx->gbc) < 4 ||
400             bytestream2_get_le32(&ctx->gbc) != MKTAG('T','D','S','B') ||
401             bytestream2_get_bytes_left(&ctx->gbc) < TDSB_HEADER_SIZE - 4) {
402             av_log(avctx, AV_LOG_ERROR, "TDSB tag is too small.\n");
403             return AVERROR_INVALIDDATA;
404         }
405 
406         tile_size = bytestream2_get_le32(&ctx->gbc);
407         if (bytestream2_get_bytes_left(&ctx->gbc) < tile_size)
408             return AVERROR_INVALIDDATA;
409 
410         tile_mode = bytestream2_get_le32(&ctx->gbc);
411         bytestream2_skip(&ctx->gbc, 4); // unknown
412         x = bytestream2_get_le32(&ctx->gbc);
413         y = bytestream2_get_le32(&ctx->gbc);
414         x2 = bytestream2_get_le32(&ctx->gbc);
415         y2 = bytestream2_get_le32(&ctx->gbc);
416 
417         if (x < 0 || y < 0 || x2 <= x || y2 <= y ||
418             x2 > ctx->width || y2 > ctx->height
419         ) {
420             av_log(avctx, AV_LOG_ERROR,
421                    "Invalid tile position (%d.%d %d.%d outside %dx%d).\n",
422                    x, y, x2, y2, ctx->width, ctx->height);
423             return AVERROR_INVALIDDATA;
424         }
425         w = x2 - x;
426         h = y2 - y;
427 
428         ret = av_reallocp(&ctx->tilebuffer, tile_size);
429         if (!ctx->tilebuffer)
430             return ret;
431 
432         bytestream2_get_buffer(&ctx->gbc, ctx->tilebuffer, tile_size);
433 
434         if (tile_mode == MKTAG('G','E','P','J')) {
435             /* Decode JPEG tile and copy it in the reference frame */
436             ret = tdsc_decode_jpeg_tile(avctx, tile_size, x, y, w, h);
437             if (ret < 0)
438                 return ret;
439         } else if (tile_mode == MKTAG(' ','W','A','R')) {
440             /* Just copy the buffer to output */
441             av_image_copy_plane(ctx->refframe->data[0] + x * 3 +
442                                 ctx->refframe->linesize[0] * y,
443                                 ctx->refframe->linesize[0], ctx->tilebuffer,
444                                 w * 3, w * 3, h);
445         } else {
446             av_log(avctx, AV_LOG_ERROR, "Unknown tile type %08x.\n", tile_mode);
447             return AVERROR_INVALIDDATA;
448         }
449         av_log(avctx, AV_LOG_DEBUG, "Tile %d, %dx%d (%d.%d)\n", i, w, h, x, y);
450     }
451 
452     return 0;
453 }
454 
tdsc_parse_tdsf(AVCodecContext * avctx,int number_tiles)455 static int tdsc_parse_tdsf(AVCodecContext *avctx, int number_tiles)
456 {
457     TDSCContext *ctx = avctx->priv_data;
458     int ret, w, h, init_refframe = !ctx->refframe->data[0];
459 
460     /* BITMAPINFOHEADER
461      * http://msdn.microsoft.com/en-us/library/windows/desktop/dd183376.aspx */
462     if (bytestream2_get_le32(&ctx->gbc) != BITMAPINFOHEADER_SIZE)
463         return AVERROR_INVALIDDATA;
464 
465     /* Store size, but wait for context reinit before updating avctx */
466     w =  bytestream2_get_le32(&ctx->gbc);
467     h = -bytestream2_get_le32(&ctx->gbc);
468 
469     if (bytestream2_get_le16(&ctx->gbc) != 1 ||  // 1 plane
470         bytestream2_get_le16(&ctx->gbc) != 24)   // BGR24
471         return AVERROR_INVALIDDATA;
472 
473     bytestream2_skip(&ctx->gbc, 24); // unused fields
474 
475     /* Update sizes */
476     if (avctx->width != w || avctx->height != h) {
477         av_log(avctx, AV_LOG_DEBUG, "Size update %dx%d -> %d%d.\n",
478                avctx->width, avctx->height, ctx->width, ctx->height);
479         ret = ff_set_dimensions(avctx, w, h);
480         if (ret < 0)
481             return ret;
482         init_refframe = 1;
483     }
484     ctx->refframe->width  = ctx->width  = w;
485     ctx->refframe->height = ctx->height = h;
486 
487     /* Allocate the reference frame if not already done or on size change */
488     if (init_refframe) {
489         ret = av_frame_get_buffer(ctx->refframe, 0);
490         if (ret < 0)
491             return ret;
492     }
493 
494     /* Decode all tiles in a frame */
495     return tdsc_decode_tiles(avctx, number_tiles);
496 }
497 
tdsc_parse_dtsm(AVCodecContext * avctx)498 static int tdsc_parse_dtsm(AVCodecContext *avctx)
499 {
500     TDSCContext *ctx = avctx->priv_data;
501     int ret;
502     int action = bytestream2_get_le32(&ctx->gbc);
503 
504     bytestream2_skip(&ctx->gbc, 4); // some kind of ID or version maybe?
505 
506     if (action == 2 || action == 3) {
507         /* Load cursor coordinates */
508         ctx->cursor_x = bytestream2_get_le32(&ctx->gbc);
509         ctx->cursor_y = bytestream2_get_le32(&ctx->gbc);
510 
511         /* Load a full cursor sprite */
512         if (action == 3) {
513             ret = tdsc_load_cursor(avctx);
514             /* Do not consider cursor errors fatal unless in explode mode */
515             if (ret < 0 && (avctx->err_recognition & AV_EF_EXPLODE))
516                 return ret;
517         }
518     } else {
519         avpriv_request_sample(avctx, "Cursor action %d", action);
520     }
521 
522     return 0;
523 }
524 
tdsc_decode_frame(AVCodecContext * avctx,AVFrame * frame,int * got_frame,AVPacket * avpkt)525 static int tdsc_decode_frame(AVCodecContext *avctx, AVFrame *frame,
526                              int *got_frame, AVPacket *avpkt)
527 {
528     TDSCContext *ctx = avctx->priv_data;
529     int ret, tag_header, keyframe = 0;
530     uLongf dlen;
531 
532     /* Resize deflate buffer on resolution change */
533     if (ctx->width != avctx->width || ctx->height != avctx->height) {
534         int deflatelen = avctx->width * avctx->height * (3 + 1);
535         if (deflatelen != ctx->deflatelen) {
536             ctx->deflatelen =deflatelen;
537             ret = av_reallocp(&ctx->deflatebuffer, ctx->deflatelen);
538             if (ret < 0) {
539                 ctx->deflatelen = 0;
540                 return ret;
541             }
542         }
543     }
544     dlen = ctx->deflatelen;
545 
546     /* Frames are deflated, need to inflate them first */
547     ret = uncompress(ctx->deflatebuffer, &dlen, avpkt->data, avpkt->size);
548     if (ret) {
549         av_log(avctx, AV_LOG_ERROR, "Deflate error %d.\n", ret);
550         return AVERROR_UNKNOWN;
551     }
552 
553     bytestream2_init(&ctx->gbc, ctx->deflatebuffer, dlen);
554 
555     /* Check for tag and for size info */
556     if (bytestream2_get_bytes_left(&ctx->gbc) < 4 + 4) {
557         av_log(avctx, AV_LOG_ERROR, "Frame is too small.\n");
558         return AVERROR_INVALIDDATA;
559     }
560 
561     /* Read tag */
562     tag_header = bytestream2_get_le32(&ctx->gbc);
563 
564     if (tag_header == MKTAG('T','D','S','F')) {
565         int number_tiles;
566         if (bytestream2_get_bytes_left(&ctx->gbc) < TDSF_HEADER_SIZE) {
567             av_log(avctx, AV_LOG_ERROR, "TDSF tag is too small.\n");
568             return AVERROR_INVALIDDATA;
569         }
570         /* First 4 bytes here are the number of GEPJ/WAR tiles in this frame */
571         number_tiles = bytestream2_get_le32(&ctx->gbc);
572 
573         bytestream2_skip(&ctx->gbc, 4); // internal timestamp maybe?
574         keyframe = bytestream2_get_le32(&ctx->gbc) == 0x30;
575 
576         ret = tdsc_parse_tdsf(avctx, number_tiles);
577         if (ret < 0)
578             return ret;
579 
580         /* Check if there is anything else we are able to parse */
581         if (bytestream2_get_bytes_left(&ctx->gbc) >= 4 + 4)
582             tag_header = bytestream2_get_le32(&ctx->gbc);
583     }
584 
585     /* This tag can be after a TDSF block or on its own frame */
586     if (tag_header == MKTAG('D','T','S','M')) {
587         /* First 4 bytes here are the total size in bytes for this frame */
588         int tag_size = bytestream2_get_le32(&ctx->gbc);
589 
590         if (bytestream2_get_bytes_left(&ctx->gbc) < tag_size) {
591             av_log(avctx, AV_LOG_ERROR, "DTSM tag is too small.\n");
592             return AVERROR_INVALIDDATA;
593         }
594 
595         ret = tdsc_parse_dtsm(avctx);
596         if (ret < 0)
597             return ret;
598     }
599 
600     /* Get the output frame and copy the reference frame */
601     ret = ff_get_buffer(avctx, frame, 0);
602     if (ret < 0)
603         return ret;
604 
605     ret = av_frame_copy(frame, ctx->refframe);
606     if (ret < 0)
607         return ret;
608 
609     /* Paint the cursor on the output frame */
610     tdsc_paint_cursor(avctx, frame->data[0], frame->linesize[0]);
611 
612     /* Frame is ready to be output */
613     if (keyframe) {
614         frame->pict_type = AV_PICTURE_TYPE_I;
615         frame->key_frame = 1;
616     } else {
617         frame->pict_type = AV_PICTURE_TYPE_P;
618     }
619     *got_frame = 1;
620 
621     return avpkt->size;
622 }
623 
624 const FFCodec ff_tdsc_decoder = {
625     .p.name         = "tdsc",
626     .p.long_name    = NULL_IF_CONFIG_SMALL("TDSC"),
627     .p.type         = AVMEDIA_TYPE_VIDEO,
628     .p.id           = AV_CODEC_ID_TDSC,
629     .init           = tdsc_init,
630     FF_CODEC_DECODE_CB(tdsc_decode_frame),
631     .close          = tdsc_close,
632     .priv_data_size = sizeof(TDSCContext),
633     .p.capabilities = AV_CODEC_CAP_DR1,
634     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE |
635                       FF_CODEC_CAP_INIT_CLEANUP,
636 };
637