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