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1 /*
2  * Mpeg video formats-related picture management functions
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include <stdint.h>
22 
23 #include "libavutil/avassert.h"
24 #include "libavutil/common.h"
25 #include "libavutil/pixdesc.h"
26 #include "libavutil/imgutils.h"
27 
28 #include "avcodec.h"
29 #include "encode.h"
30 #include "motion_est.h"
31 #include "mpegpicture.h"
32 #include "mpegutils.h"
33 #include "threadframe.h"
34 
free_picture_tables(Picture * pic)35 static void av_noinline free_picture_tables(Picture *pic)
36 {
37     pic->alloc_mb_width  =
38     pic->alloc_mb_height = 0;
39 
40     av_buffer_unref(&pic->mb_var_buf);
41     av_buffer_unref(&pic->mc_mb_var_buf);
42     av_buffer_unref(&pic->mb_mean_buf);
43     av_buffer_unref(&pic->mbskip_table_buf);
44     av_buffer_unref(&pic->qscale_table_buf);
45     av_buffer_unref(&pic->mb_type_buf);
46 
47     for (int i = 0; i < 2; i++) {
48         av_buffer_unref(&pic->motion_val_buf[i]);
49         av_buffer_unref(&pic->ref_index_buf[i]);
50     }
51 }
52 
make_tables_writable(Picture * pic)53 static int make_tables_writable(Picture *pic)
54 {
55     int ret, i;
56 #define MAKE_WRITABLE(table) \
57 do {\
58     if (pic->table &&\
59        (ret = av_buffer_make_writable(&pic->table)) < 0)\
60     return ret;\
61 } while (0)
62 
63     MAKE_WRITABLE(mb_var_buf);
64     MAKE_WRITABLE(mc_mb_var_buf);
65     MAKE_WRITABLE(mb_mean_buf);
66     MAKE_WRITABLE(mbskip_table_buf);
67     MAKE_WRITABLE(qscale_table_buf);
68     MAKE_WRITABLE(mb_type_buf);
69 
70     for (i = 0; i < 2; i++) {
71         MAKE_WRITABLE(motion_val_buf[i]);
72         MAKE_WRITABLE(ref_index_buf[i]);
73     }
74 
75     return 0;
76 }
77 
ff_mpeg_framesize_alloc(AVCodecContext * avctx,MotionEstContext * me,ScratchpadContext * sc,int linesize)78 int ff_mpeg_framesize_alloc(AVCodecContext *avctx, MotionEstContext *me,
79                             ScratchpadContext *sc, int linesize)
80 {
81 #   define EMU_EDGE_HEIGHT (4 * 70)
82     int alloc_size = FFALIGN(FFABS(linesize) + 64, 32);
83 
84     if (avctx->hwaccel)
85         return 0;
86 
87     if (linesize < 24) {
88         av_log(avctx, AV_LOG_ERROR, "Image too small, temporary buffers cannot function\n");
89         return AVERROR_PATCHWELCOME;
90     }
91 
92     if (av_image_check_size2(alloc_size, EMU_EDGE_HEIGHT, avctx->max_pixels, AV_PIX_FMT_NONE, 0, avctx) < 0)
93         return AVERROR(ENOMEM);
94 
95     // edge emu needs blocksize + filter length - 1
96     // (= 17x17 for  halfpel / 21x21 for H.264)
97     // VC-1 computes luma and chroma simultaneously and needs 19X19 + 9x9
98     // at uvlinesize. It supports only YUV420 so 24x24 is enough
99     // linesize * interlaced * MBsize
100     // we also use this buffer for encoding in encode_mb_internal() needig an additional 32 lines
101     if (!FF_ALLOCZ_TYPED_ARRAY(sc->edge_emu_buffer, alloc_size * EMU_EDGE_HEIGHT) ||
102         !FF_ALLOCZ_TYPED_ARRAY(me->scratchpad,      alloc_size * 4 * 16 * 2)) {
103         av_freep(&sc->edge_emu_buffer);
104         return AVERROR(ENOMEM);
105     }
106 
107     me->temp            = me->scratchpad;
108     sc->rd_scratchpad   = me->scratchpad;
109     sc->b_scratchpad    = me->scratchpad;
110     sc->obmc_scratchpad = me->scratchpad + 16;
111 
112     return 0;
113 }
114 
115 /**
116  * Allocate a frame buffer
117  */
alloc_frame_buffer(AVCodecContext * avctx,Picture * pic,MotionEstContext * me,ScratchpadContext * sc,int chroma_x_shift,int chroma_y_shift,int linesize,int uvlinesize)118 static int alloc_frame_buffer(AVCodecContext *avctx,  Picture *pic,
119                               MotionEstContext *me, ScratchpadContext *sc,
120                               int chroma_x_shift, int chroma_y_shift,
121                               int linesize, int uvlinesize)
122 {
123     int edges_needed = av_codec_is_encoder(avctx->codec);
124     int r, ret;
125 
126     pic->tf.f = pic->f;
127 
128     if (edges_needed) {
129         pic->f->width  = avctx->width  + 2 * EDGE_WIDTH;
130         pic->f->height = avctx->height + 2 * EDGE_WIDTH;
131 
132         r = ff_encode_alloc_frame(avctx, pic->f);
133     } else if (avctx->codec_id != AV_CODEC_ID_WMV3IMAGE &&
134                avctx->codec_id != AV_CODEC_ID_VC1IMAGE  &&
135                avctx->codec_id != AV_CODEC_ID_MSS2) {
136         r = ff_thread_get_ext_buffer(avctx, &pic->tf,
137                                      pic->reference ? AV_GET_BUFFER_FLAG_REF : 0);
138     } else {
139         pic->f->width  = avctx->width;
140         pic->f->height = avctx->height;
141         pic->f->format = avctx->pix_fmt;
142         r = avcodec_default_get_buffer2(avctx, pic->f, 0);
143     }
144 
145     if (r < 0 || !pic->f->buf[0]) {
146         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed (%d %p)\n",
147                r, pic->f->data[0]);
148         return -1;
149     }
150 
151     if (edges_needed) {
152         int i;
153         for (i = 0; pic->f->data[i]; i++) {
154             int offset = (EDGE_WIDTH >> (i ? chroma_y_shift : 0)) *
155                          pic->f->linesize[i] +
156                          (EDGE_WIDTH >> (i ? chroma_x_shift : 0));
157             pic->f->data[i] += offset;
158         }
159         pic->f->width  = avctx->width;
160         pic->f->height = avctx->height;
161     }
162 
163     if (avctx->hwaccel) {
164         assert(!pic->hwaccel_picture_private);
165         if (avctx->hwaccel->frame_priv_data_size) {
166             pic->hwaccel_priv_buf = av_buffer_allocz(avctx->hwaccel->frame_priv_data_size);
167             if (!pic->hwaccel_priv_buf) {
168                 av_log(avctx, AV_LOG_ERROR, "alloc_frame_buffer() failed (hwaccel private data allocation)\n");
169                 return -1;
170             }
171             pic->hwaccel_picture_private = pic->hwaccel_priv_buf->data;
172         }
173     }
174 
175     if ((linesize   &&   linesize != pic->f->linesize[0]) ||
176         (uvlinesize && uvlinesize != pic->f->linesize[1])) {
177         av_log(avctx, AV_LOG_ERROR,
178                "get_buffer() failed (stride changed: linesize=%d/%d uvlinesize=%d/%d)\n",
179                linesize,   pic->f->linesize[0],
180                uvlinesize, pic->f->linesize[1]);
181         ff_mpeg_unref_picture(avctx, pic);
182         return -1;
183     }
184 
185     if (av_pix_fmt_count_planes(pic->f->format) > 2 &&
186         pic->f->linesize[1] != pic->f->linesize[2]) {
187         av_log(avctx, AV_LOG_ERROR,
188                "get_buffer() failed (uv stride mismatch)\n");
189         ff_mpeg_unref_picture(avctx, pic);
190         return -1;
191     }
192 
193     if (!sc->edge_emu_buffer &&
194         (ret = ff_mpeg_framesize_alloc(avctx, me, sc,
195                                        pic->f->linesize[0])) < 0) {
196         av_log(avctx, AV_LOG_ERROR,
197                "get_buffer() failed to allocate context scratch buffers.\n");
198         ff_mpeg_unref_picture(avctx, pic);
199         return ret;
200     }
201 
202     return 0;
203 }
204 
alloc_picture_tables(AVCodecContext * avctx,Picture * pic,int encoding,int out_format,int mb_stride,int mb_width,int mb_height,int b8_stride)205 static int alloc_picture_tables(AVCodecContext *avctx, Picture *pic, int encoding, int out_format,
206                                 int mb_stride, int mb_width, int mb_height, int b8_stride)
207 {
208     const int big_mb_num    = mb_stride * (mb_height + 1) + 1;
209     const int mb_array_size = mb_stride * mb_height;
210     const int b8_array_size = b8_stride * mb_height * 2;
211     int i;
212 
213 
214     pic->mbskip_table_buf = av_buffer_allocz(mb_array_size + 2);
215     pic->qscale_table_buf = av_buffer_allocz(big_mb_num + mb_stride);
216     pic->mb_type_buf      = av_buffer_allocz((big_mb_num + mb_stride) *
217                                              sizeof(uint32_t));
218     if (!pic->mbskip_table_buf || !pic->qscale_table_buf || !pic->mb_type_buf)
219         return AVERROR(ENOMEM);
220 
221     if (encoding) {
222         pic->mb_var_buf    = av_buffer_allocz(mb_array_size * sizeof(int16_t));
223         pic->mc_mb_var_buf = av_buffer_allocz(mb_array_size * sizeof(int16_t));
224         pic->mb_mean_buf   = av_buffer_allocz(mb_array_size);
225         if (!pic->mb_var_buf || !pic->mc_mb_var_buf || !pic->mb_mean_buf)
226             return AVERROR(ENOMEM);
227     }
228 
229     if (out_format == FMT_H263 || encoding ||
230         (avctx->export_side_data & AV_CODEC_EXPORT_DATA_MVS)) {
231         int mv_size        = 2 * (b8_array_size + 4) * sizeof(int16_t);
232         int ref_index_size = 4 * mb_array_size;
233 
234         for (i = 0; mv_size && i < 2; i++) {
235             pic->motion_val_buf[i] = av_buffer_allocz(mv_size);
236             pic->ref_index_buf[i]  = av_buffer_allocz(ref_index_size);
237             if (!pic->motion_val_buf[i] || !pic->ref_index_buf[i])
238                 return AVERROR(ENOMEM);
239         }
240     }
241 
242     pic->alloc_mb_width  = mb_width;
243     pic->alloc_mb_height = mb_height;
244     pic->alloc_mb_stride = mb_stride;
245 
246     return 0;
247 }
248 
249 /**
250  * Allocate a Picture.
251  * The pixels are allocated/set by calling get_buffer() if shared = 0
252  */
ff_alloc_picture(AVCodecContext * avctx,Picture * pic,MotionEstContext * me,ScratchpadContext * sc,int shared,int encoding,int chroma_x_shift,int chroma_y_shift,int out_format,int mb_stride,int mb_width,int mb_height,int b8_stride,ptrdiff_t * linesize,ptrdiff_t * uvlinesize)253 int ff_alloc_picture(AVCodecContext *avctx, Picture *pic, MotionEstContext *me,
254                      ScratchpadContext *sc, int shared, int encoding,
255                      int chroma_x_shift, int chroma_y_shift, int out_format,
256                      int mb_stride, int mb_width, int mb_height, int b8_stride,
257                      ptrdiff_t *linesize, ptrdiff_t *uvlinesize)
258 {
259     int i, ret;
260 
261     if (pic->qscale_table_buf)
262         if (   pic->alloc_mb_width  != mb_width
263             || pic->alloc_mb_height != mb_height)
264             free_picture_tables(pic);
265 
266     if (shared) {
267         av_assert0(pic->f->data[0]);
268         pic->shared = 1;
269     } else {
270         av_assert0(!pic->f->buf[0]);
271         if (alloc_frame_buffer(avctx, pic, me, sc,
272                                chroma_x_shift, chroma_y_shift,
273                                *linesize, *uvlinesize) < 0)
274             return -1;
275 
276         *linesize   = pic->f->linesize[0];
277         *uvlinesize = pic->f->linesize[1];
278     }
279 
280     if (!pic->qscale_table_buf)
281         ret = alloc_picture_tables(avctx, pic, encoding, out_format,
282                                    mb_stride, mb_width, mb_height, b8_stride);
283     else
284         ret = make_tables_writable(pic);
285     if (ret < 0)
286         goto fail;
287 
288     if (encoding) {
289         pic->mb_var    = (uint16_t*)pic->mb_var_buf->data;
290         pic->mc_mb_var = (uint16_t*)pic->mc_mb_var_buf->data;
291         pic->mb_mean   = pic->mb_mean_buf->data;
292     }
293 
294     pic->mbskip_table = pic->mbskip_table_buf->data;
295     pic->qscale_table = pic->qscale_table_buf->data + 2 * mb_stride + 1;
296     pic->mb_type      = (uint32_t*)pic->mb_type_buf->data + 2 * mb_stride + 1;
297 
298     if (pic->motion_val_buf[0]) {
299         for (i = 0; i < 2; i++) {
300             pic->motion_val[i] = (int16_t (*)[2])pic->motion_val_buf[i]->data + 4;
301             pic->ref_index[i]  = pic->ref_index_buf[i]->data;
302         }
303     }
304 
305     return 0;
306 fail:
307     av_log(avctx, AV_LOG_ERROR, "Error allocating a picture.\n");
308     ff_mpeg_unref_picture(avctx, pic);
309     free_picture_tables(pic);
310     return AVERROR(ENOMEM);
311 }
312 
313 /**
314  * Deallocate a picture; frees the picture tables in case they
315  * need to be reallocated anyway.
316  */
ff_mpeg_unref_picture(AVCodecContext * avctx,Picture * pic)317 void ff_mpeg_unref_picture(AVCodecContext *avctx, Picture *pic)
318 {
319     int off = offsetof(Picture, mb_mean) + sizeof(pic->mb_mean);
320 
321     pic->tf.f = pic->f;
322     /* WM Image / Screen codecs allocate internal buffers with different
323      * dimensions / colorspaces; ignore user-defined callbacks for these. */
324     if (avctx->codec_id != AV_CODEC_ID_WMV3IMAGE &&
325         avctx->codec_id != AV_CODEC_ID_VC1IMAGE  &&
326         avctx->codec_id != AV_CODEC_ID_MSS2)
327         ff_thread_release_ext_buffer(avctx, &pic->tf);
328     else if (pic->f)
329         av_frame_unref(pic->f);
330 
331     av_buffer_unref(&pic->hwaccel_priv_buf);
332 
333     if (pic->needs_realloc)
334         free_picture_tables(pic);
335 
336     memset((uint8_t*)pic + off, 0, sizeof(*pic) - off);
337 }
338 
ff_update_picture_tables(Picture * dst,const Picture * src)339 int ff_update_picture_tables(Picture *dst, const Picture *src)
340 {
341     int i, ret;
342 
343     ret  = av_buffer_replace(&dst->mb_var_buf,       src->mb_var_buf);
344     ret |= av_buffer_replace(&dst->mc_mb_var_buf,    src->mc_mb_var_buf);
345     ret |= av_buffer_replace(&dst->mb_mean_buf,      src->mb_mean_buf);
346     ret |= av_buffer_replace(&dst->mbskip_table_buf, src->mbskip_table_buf);
347     ret |= av_buffer_replace(&dst->qscale_table_buf, src->qscale_table_buf);
348     ret |= av_buffer_replace(&dst->mb_type_buf,      src->mb_type_buf);
349     for (i = 0; i < 2; i++) {
350         ret |= av_buffer_replace(&dst->motion_val_buf[i], src->motion_val_buf[i]);
351         ret |= av_buffer_replace(&dst->ref_index_buf[i],  src->ref_index_buf[i]);
352     }
353 
354     if (ret < 0) {
355         free_picture_tables(dst);
356         return ret;
357     }
358 
359     dst->mb_var        = src->mb_var;
360     dst->mc_mb_var     = src->mc_mb_var;
361     dst->mb_mean       = src->mb_mean;
362     dst->mbskip_table  = src->mbskip_table;
363     dst->qscale_table  = src->qscale_table;
364     dst->mb_type       = src->mb_type;
365     for (i = 0; i < 2; i++) {
366         dst->motion_val[i] = src->motion_val[i];
367         dst->ref_index[i]  = src->ref_index[i];
368     }
369 
370     dst->alloc_mb_width  = src->alloc_mb_width;
371     dst->alloc_mb_height = src->alloc_mb_height;
372     dst->alloc_mb_stride = src->alloc_mb_stride;
373 
374     return 0;
375 }
376 
ff_mpeg_ref_picture(AVCodecContext * avctx,Picture * dst,Picture * src)377 int ff_mpeg_ref_picture(AVCodecContext *avctx, Picture *dst, Picture *src)
378 {
379     int ret;
380 
381     av_assert0(!dst->f->buf[0]);
382     av_assert0(src->f->buf[0]);
383 
384     src->tf.f = src->f;
385     dst->tf.f = dst->f;
386     ret = ff_thread_ref_frame(&dst->tf, &src->tf);
387     if (ret < 0)
388         goto fail;
389 
390     ret = ff_update_picture_tables(dst, src);
391     if (ret < 0)
392         goto fail;
393 
394     if (src->hwaccel_picture_private) {
395         dst->hwaccel_priv_buf = av_buffer_ref(src->hwaccel_priv_buf);
396         if (!dst->hwaccel_priv_buf) {
397             ret = AVERROR(ENOMEM);
398             goto fail;
399         }
400         dst->hwaccel_picture_private = dst->hwaccel_priv_buf->data;
401     }
402 
403     dst->field_picture           = src->field_picture;
404     dst->mb_var_sum              = src->mb_var_sum;
405     dst->mc_mb_var_sum           = src->mc_mb_var_sum;
406     dst->b_frame_score           = src->b_frame_score;
407     dst->needs_realloc           = src->needs_realloc;
408     dst->reference               = src->reference;
409     dst->shared                  = src->shared;
410 
411     memcpy(dst->encoding_error, src->encoding_error,
412            sizeof(dst->encoding_error));
413 
414     return 0;
415 fail:
416     ff_mpeg_unref_picture(avctx, dst);
417     return ret;
418 }
419 
pic_is_unused(Picture * pic)420 static inline int pic_is_unused(Picture *pic)
421 {
422     if (!pic->f->buf[0])
423         return 1;
424     if (pic->needs_realloc)
425         return 1;
426     return 0;
427 }
428 
find_unused_picture(AVCodecContext * avctx,Picture * picture,int shared)429 static int find_unused_picture(AVCodecContext *avctx, Picture *picture, int shared)
430 {
431     int i;
432 
433     if (shared) {
434         for (i = 0; i < MAX_PICTURE_COUNT; i++) {
435             if (!picture[i].f->buf[0])
436                 return i;
437         }
438     } else {
439         for (i = 0; i < MAX_PICTURE_COUNT; i++) {
440             if (pic_is_unused(&picture[i]))
441                 return i;
442         }
443     }
444 
445     av_log(avctx, AV_LOG_FATAL,
446            "Internal error, picture buffer overflow\n");
447     /* We could return -1, but the codec would crash trying to draw into a
448      * non-existing frame anyway. This is safer than waiting for a random crash.
449      * Also the return of this is never useful, an encoder must only allocate
450      * as much as allowed in the specification. This has no relationship to how
451      * much libavcodec could allocate (and MAX_PICTURE_COUNT is always large
452      * enough for such valid streams).
453      * Plus, a decoder has to check stream validity and remove frames if too
454      * many reference frames are around. Waiting for "OOM" is not correct at
455      * all. Similarly, missing reference frames have to be replaced by
456      * interpolated/MC frames, anything else is a bug in the codec ...
457      */
458     abort();
459     return -1;
460 }
461 
ff_find_unused_picture(AVCodecContext * avctx,Picture * picture,int shared)462 int ff_find_unused_picture(AVCodecContext *avctx, Picture *picture, int shared)
463 {
464     int ret = find_unused_picture(avctx, picture, shared);
465 
466     if (ret >= 0 && ret < MAX_PICTURE_COUNT) {
467         if (picture[ret].needs_realloc) {
468             ff_mpeg_unref_picture(avctx, &picture[ret]);
469         }
470     }
471     return ret;
472 }
473 
ff_mpv_picture_free(AVCodecContext * avctx,Picture * pic)474 void av_cold ff_mpv_picture_free(AVCodecContext *avctx, Picture *pic)
475 {
476     free_picture_tables(pic);
477     ff_mpeg_unref_picture(avctx, pic);
478     av_frame_free(&pic->f);
479 }
480