FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavcodec/leaddec.c
Date: 2025-08-19 23:55:23
Exec Total Coverage
Lines: 143 165 86.7%
Functions: 6 6 100.0%
Branches: 106 123 86.2%
Line Branch Exec Source
1 /*
2 * LEAD MCMP decoder
3 *
4 * Copyright (c) 2023 Peter Ross
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 "blockdsp.h"
25 #include "codec_internal.h"
26 #include "copy_block.h"
27 #include "decode.h"
28 #include "get_bits.h"
29 #include "idctdsp.h"
30 #include "jpegquanttables.h"
31 #include "jpegtables.h"
32 #include "leaddata.h"
33 #include "libavutil/mem.h"
34 #include "libavutil/mem_internal.h"
35 #include "libavutil/thread.h"
36
37 #define LUMA_DC_BITS 9
38 #define CHROMA_DC_BITS 11
39 #define LUMA_AC_BITS 10
40 #define CHROMA_AC_BITS 10
41
42 static VLCElem luma_dc_vlc[1 << LUMA_DC_BITS];
43 static VLCElem chroma_dc_vlc[1 << CHROMA_DC_BITS];
44 static VLCElem luma_ac_vlc[1160];
45 static VLCElem chroma_ac_vlc[1160];
46
47 4 static av_cold void lead_init_static_data(void)
48 {
49 4 VLC_INIT_STATIC_TABLE_FROM_LENGTHS(luma_dc_vlc, LUMA_DC_BITS, FF_ARRAY_ELEMS(luma_dc_len),
50 luma_dc_len, 1,
51 NULL, 0, 0,
52 0, 0);
53 4 VLC_INIT_STATIC_TABLE_FROM_LENGTHS(chroma_dc_vlc, CHROMA_DC_BITS, FF_ARRAY_ELEMS(chroma_dc_len),
54 chroma_dc_len, 1,
55 NULL, 0, 0,
56 0, 0);
57 4 VLC_INIT_STATIC_TABLE_FROM_LENGTHS(luma_ac_vlc, LUMA_AC_BITS, FF_ARRAY_ELEMS(luma_ac_len),
58 luma_ac_len, 1,
59 ff_mjpeg_val_ac_luminance, 1, 1,
60 0, 0);
61 4 VLC_INIT_STATIC_TABLE_FROM_LENGTHS(chroma_ac_vlc, CHROMA_AC_BITS, FF_ARRAY_ELEMS(chroma_ac_len),
62 chroma_ac_len, 1,
63 ff_mjpeg_val_ac_chrominance, 1, 1,
64 0, 0);
65 4 }
66
67 typedef struct LeadContext {
68 uint8_t *bitstream_buf;
69 unsigned int bitstream_buf_size;
70 BlockDSPContext bdsp;
71 IDCTDSPContext idsp;
72 uint8_t permutated_scantable[64];
73 } LeadContext;
74
75 8 static av_cold int lead_decode_init(AVCodecContext * avctx)
76 {
77 static AVOnce init_static_once = AV_ONCE_INIT;
78 8 LeadContext *s = avctx->priv_data;
79
80
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 8 if (avctx->extradata_size < 20)
81 ✗ return AVERROR_INVALIDDATA;
82
83 8 ff_blockdsp_init(&s->bdsp);
84 8 ff_idctdsp_init(&s->idsp, avctx);
85 8 ff_permute_scantable(s->permutated_scantable, ff_zigzag_direct, s->idsp.idct_permutation);
86
87 8 ff_thread_once(&init_static_once, lead_init_static_data);
88
89 8 return 0;
90 }
91
92 16 static void calc_dequant(uint16_t * dequant, const uint8_t * quant_tbl, int q)
93 {
94
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 1040 for (int i = 0; i < 64; i++)
95 1024 dequant[i] = av_clip(q * quant_tbl[ff_zigzag_direct[i]] / 50, 2, 32767);
96 16 }
97
98 21936 static int decode_block(LeadContext * s, GetBitContext * gb,
99 const VLCElem * dc_table, int dc_bits, const VLCElem * ac_table, int ac_bits,
100 int16_t * dc_pred, const uint16_t * dequant,
101 uint8_t * dst, int stride)
102 {
103 DECLARE_ALIGNED(32, int16_t, block)[64];
104 int size;
105
106 21936 s->bdsp.clear_block(block);
107
108
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 21936 if (get_bits_left(gb) <= 0)
109 ✗ return AVERROR_INVALIDDATA;
110
111 21936 size = get_vlc2(gb, dc_table, dc_bits, 1);
112
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 21936 if (size < 0)
113 ✗ return AVERROR_INVALIDDATA;
114
115
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 21936 if (size)
116 16492 *dc_pred += get_xbits(gb, size);
117
118 21936 block[0] = (1 << 10) + *dc_pred * dequant[0];
119
120
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 188120 for (int i = 1; i < 64; i++) {
121 188020 int symbol = get_vlc2(gb, ac_table, ac_bits, 2);
122
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 188020 if (symbol < 0)
123 ✗ return AVERROR_INVALIDDATA;
124
125
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 188020 if (!symbol)
126 21836 break;
127
128 166184 i += symbol >> 4;
129
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 166184 if (i >= 64)
130 ✗ return AVERROR_INVALIDDATA;
131
132 166184 size = symbol & 0xF;
133
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 166184 if (size)
134 165806 block[s->permutated_scantable[i]] = get_xbits(gb, size) * dequant[i];
135 }
136
137 21936 s->idsp.idct_put(dst, stride, block);
138 21936 return 0;
139 }
140
141 8 static int lead_decode_frame(AVCodecContext *avctx, AVFrame * frame,
142 int * got_frame, AVPacket * avpkt)
143 {
144 8 LeadContext *s = avctx->priv_data;
145 8 const uint8_t * buf = avpkt->data;
146 8 int ret, format, zero = 0, yuv20p_half = 0, fields = 1, q, size;
147 GetBitContext gb;
148 8 int16_t dc_pred[3] = {0, 0, 0};
149 uint16_t dequant[2][64];
150
151
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 8 if (avpkt->size < 8)
152 ✗ return AVERROR_INVALIDDATA;
153
154 8 format = AV_RL16(buf + 4);
155
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 8 switch(format) {
156 2 case 0x0:
157 2 zero = 1;
158 2 avctx->pix_fmt = AV_PIX_FMT_YUV420P;
159 2 break;
160 2 case 0x6:
161 case 0x8000:
162 2 yuv20p_half = 1;
163 // fall-through
164 4 case 0x1000:
165 4 avctx->pix_fmt = AV_PIX_FMT_YUV420P;
166 4 break;
167 ✗ case 0x1006:
168 ✗ fields = 2;
169 ✗ avctx->pix_fmt = AV_PIX_FMT_YUV420P;
170 ✗ break;
171 ✗ case 0x2000:
172 ✗ avctx->pix_fmt = AV_PIX_FMT_YUV444P;
173 ✗ break;
174 2 case 0x2006:
175 2 avctx->pix_fmt = AV_PIX_FMT_YUV444P;
176 2 fields = 2;
177 2 break;
178 ✗ default:
179 ✗ avpriv_request_sample(avctx, "unsupported format 0x%x", format);
180 ✗ return AVERROR_PATCHWELCOME;
181 }
182
183 8 q = AV_RL16(buf + 6);
184 8 calc_dequant(dequant[0], ff_mjpeg_std_luminance_quant_tbl, q);
185 8 calc_dequant(dequant[1], ff_mjpeg_std_chrominance_quant_tbl, q);
186
187
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 8 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
188 ✗ return ret;
189
190 8 av_fast_padded_malloc(&s->bitstream_buf, &s->bitstream_buf_size, avpkt->size - 8);
191
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 8 if (!s->bitstream_buf)
192 ✗ return AVERROR(ENOMEM);
193
194 8 size = 0;
195
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 175066 for (int i = 8; i < avpkt->size; i++) {
196 175058 int src = buf[i] ^ 0x80;
197 175058 s->bitstream_buf[size++] = src;
198
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 175058 if (src == 0xFF && i + 1 < avpkt->size && (buf[i + 1] ^ 0x80) == 0x00)
199 2554 i++;
200 }
201
202 8 ret = init_get_bits8(&gb, s->bitstream_buf, size);
203
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 8 if (ret < 0)
204 ✗ return ret;
205
206
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 8 if (avctx->pix_fmt == AV_PIX_FMT_YUV420P && zero) {
207
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 74 for (int mb_y = 0; mb_y < avctx->height / 8; mb_y++)
208
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 1656 for (int mb_x = 0; mb_x < avctx->width / 16; mb_x++)
209
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 7920 for (int b = 0; b < 4; b++) {
210 6336 int luma_block = 2;
211
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 6336 const VLCElem * dc_vlc = b < luma_block ? luma_dc_vlc : chroma_dc_vlc;
212
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 6336 int dc_bits = b < luma_block ? LUMA_DC_BITS : CHROMA_DC_BITS;
213
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 6336 const VLCElem * ac_vlc = b < luma_block ? luma_ac_vlc : chroma_ac_vlc;
214 6336 int ac_bits = b < luma_block ? LUMA_AC_BITS : CHROMA_AC_BITS;
215
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 6336 int plane = b < luma_block ? 0 : b - 1;
216 int x, y, yclip;
217
218
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 6336 if (b < luma_block) {
219 3168 y = 8*mb_y + 8*(b >> 1);
220 3168 x = 16*mb_x + 8*(b & 1);
221 3168 yclip = 0;
222 } else {
223 3168 y = 4*mb_y;
224 3168 x = 8*mb_x;
225 3168 yclip = y + 8 >= avctx->height / 2;
226 }
227
228
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 6336 if (yclip) {
229 uint8_t tmp[64];
230 176 ret = decode_block(s, &gb, dc_vlc, dc_bits, ac_vlc, ac_bits,
231 176 dc_pred + plane, dequant[!(b < 4)], tmp, 8);
232
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 1232 for (int yy = 0; yy < 8 && y + yy < avctx->height / 2; yy++)
233 1056 memcpy(frame->data[plane] + (y+yy)*frame->linesize[plane] + x, tmp + yy, 8);
234 } else {
235 6160 ret = decode_block(s, &gb, dc_vlc, dc_bits, ac_vlc, ac_bits,
236 6160 dc_pred + plane, dequant[!(b < 4)],
237 6160 frame->data[plane] + y*frame->linesize[plane] + x,
238 frame->linesize[plane]);
239 }
240
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 6336 if (ret < 0)
241 ✗ return ret;
242 }
243
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 6 } else if (avctx->pix_fmt == AV_PIX_FMT_YUV420P) {
244
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 8 for (int f = 0; f < fields; f++)
245
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 74 for (int mb_y = 0; mb_y < (avctx->height + 15) / 16 / fields; mb_y++)
246
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 1870 for (int mb_x = 0; mb_x < (avctx->width + 15) / 16; mb_x++)
247
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 10200 for (int b = 0; b < (yuv20p_half ? 4 : 6); b++) {
248
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 8400 int luma_block = yuv20p_half ? 2 : 4;
249
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 8400 const VLCElem * dc_vlc = b < luma_block ? luma_dc_vlc : chroma_dc_vlc;
250
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 8400 int dc_bits = b < luma_block ? LUMA_DC_BITS : CHROMA_DC_BITS;
251
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 8400 const VLCElem * ac_vlc = b < luma_block ? luma_ac_vlc : chroma_ac_vlc;
252 8400 int ac_bits = b < luma_block ? LUMA_AC_BITS : CHROMA_AC_BITS;
253
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 8400 int plane = b < luma_block ? 0 : b - (yuv20p_half ? 1 : 3);
254 int x, y;
255
256
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 8400 if (b < luma_block) {
257 4800 y = 16*mb_y + 8*(b >> 1);
258 4800 x = 16*mb_x + 8*(b & 1);
259 } else {
260 3600 y = 8*mb_y;
261 3600 x = 8*mb_x;
262 }
263
264 8400 ret = decode_block(s, &gb, dc_vlc, dc_bits, ac_vlc, ac_bits,
265 8400 dc_pred + plane, dequant[!(b < 4)],
266 8400 frame->data[plane] + (f + y*fields)*frame->linesize[plane] + x,
267
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 8400 (yuv20p_half && b < 2 ? 2 : 1) * fields * frame->linesize[plane]);
268
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 8400 if (ret < 0)
269 ✗ return ret;
270
271
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 8400 if (yuv20p_half && b < 2)
272 2400 copy_block8(frame->data[plane] + (y + 1)*frame->linesize[plane] + x,
273 2400 frame->data[plane] + y*frame->linesize[plane] + x,
274 2400 2*frame->linesize[plane], 2*frame->linesize[plane], 8);
275 }
276 } else {
277
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 6 for (int f = 0; f < fields; f++)
278
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 64 for (int j = 0; j < (avctx->height + 7) / fields / 8; j++)
279
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 2460 for (int i = 0; i < (avctx->width + 7) / 8; i++)
280
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 9600 for (int plane = 0; plane < 3; plane++) {
281
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 7200 const VLCElem * dc_vlc = !plane ? luma_dc_vlc : chroma_dc_vlc;
282
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 7200 int dc_bits = !plane ? LUMA_DC_BITS : CHROMA_DC_BITS;
283
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 7200 const VLCElem * ac_vlc = !plane ? luma_ac_vlc : chroma_ac_vlc;
284 7200 int ac_bits = !plane ? LUMA_AC_BITS : CHROMA_AC_BITS;
285
286 7200 ret = decode_block(s, &gb, dc_vlc, dc_bits, ac_vlc, ac_bits,
287 7200 dc_pred + plane, dequant[!!plane],
288 7200 frame->data[plane] + (f + 8*j*fields)*frame->linesize[plane] + 8*i,
289 7200 fields * frame->linesize[plane]);
290
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 7200 if (ret < 0)
291 ✗ return ret;
292 }
293 }
294
295 8 *got_frame = 1;
296
297 8 return avpkt->size;
298 }
299
300 8 static av_cold int lead_decode_end(AVCodecContext * avctx)
301 {
302 8 LeadContext *s = avctx->priv_data;
303
304 8 av_freep(&s->bitstream_buf);
305
306 8 return 0;
307 }
308
309 const FFCodec ff_lead_decoder = {
310 .p.name = "lead",
311 CODEC_LONG_NAME("LEAD MCMP"),
312 .p.type = AVMEDIA_TYPE_VIDEO,
313 .p.id = AV_CODEC_ID_LEAD,
314 .priv_data_size = sizeof(LeadContext),
315 .init = lead_decode_init,
316 .close = lead_decode_end,
317 FF_CODEC_DECODE_CB(lead_decode_frame),
318 .p.capabilities = AV_CODEC_CAP_DR1,
319 .caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
320 };
321