1 /*
2  * VBLE Decoder
3  * Copyright (c) 2011 Derek Buitenhuis
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  * VBLE Decoder
25  */
26 
27 #include "libavutil/imgutils.h"
28 
29 #define BITSTREAM_READER_LE
30 #include "avcodec.h"
31 #include "codec_internal.h"
32 #include "get_bits.h"
33 #include "lossless_videodsp.h"
34 #include "mathops.h"
35 #include "thread.h"
36 
37 typedef struct VBLEContext {
38     AVCodecContext *avctx;
39     LLVidDSPContext llviddsp;
40 
41     int            size;
42     uint8_t        *val; ///< This array first holds the lengths of vlc symbols and then their value.
43 } VBLEContext;
44 
vble_unpack(VBLEContext *ctx, GetBitContext *gb)45 static int vble_unpack(VBLEContext *ctx, GetBitContext *gb)
46 {
47     int i;
48     int allbits = 0;
49     static const uint8_t LUT[256] = {
50         8,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
51         5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
52         6,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
53         5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
54         7,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
55         5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
56         6,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
57         5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
58     };
59 
60     /* Read all the lengths in first */
61     for (i = 0; i < ctx->size; i++) {
62         /* At most we need to read 9 bits total to get indices up to 8 */
63         int val = show_bits(gb, 8);
64 
65         // read reverse unary
66         if (val) {
67             val = LUT[val];
68             skip_bits(gb, val + 1);
69             ctx->val[i] = val;
70         } else {
71             skip_bits(gb, 8);
72             if (!get_bits1(gb))
73                 return -1;
74             ctx->val[i] = 8;
75         }
76         allbits += ctx->val[i];
77     }
78 
79     /* Check we have enough bits left */
80     if (get_bits_left(gb) < allbits)
81         return -1;
82     return 0;
83 }
84 
vble_restore_plane(VBLEContext *ctx, AVFrame *pic, GetBitContext *gb, int plane, int offset, int width, int height)85 static void vble_restore_plane(VBLEContext *ctx, AVFrame *pic,
86                                GetBitContext *gb, int plane,
87                                int offset, int width, int height)
88 {
89     uint8_t *dst = pic->data[plane];
90     uint8_t *val = ctx->val + offset;
91     int stride = pic->linesize[plane];
92     int i, j, left, left_top;
93 
94     for (i = 0; i < height; i++) {
95         for (j = 0; j < width; j++) {
96             /* get_bits can't take a length of 0 */
97             if (val[j]) {
98                 int v = (1 << val[j]) + get_bits(gb, val[j]) - 1;
99                 val[j] = (v >> 1) ^ -(v & 1);
100             }
101         }
102         if (i) {
103             left = 0;
104             left_top = dst[-stride];
105             ctx->llviddsp.add_median_pred(dst, dst - stride, val,
106                                           width, &left, &left_top);
107         } else {
108             dst[0] = val[0];
109             for (j = 1; j < width; j++)
110                 dst[j] = val[j] + dst[j - 1];
111         }
112         dst += stride;
113         val += width;
114     }
115 }
116 
vble_decode_frame(AVCodecContext *avctx, AVFrame *pic, int *got_frame, AVPacket *avpkt)117 static int vble_decode_frame(AVCodecContext *avctx, AVFrame *pic,
118                              int *got_frame, AVPacket *avpkt)
119 {
120     VBLEContext *ctx = avctx->priv_data;
121     GetBitContext gb;
122     const uint8_t *src = avpkt->data;
123     int version;
124     int offset = 0;
125     int width_uv = avctx->width / 2, height_uv = avctx->height / 2;
126     int ret;
127 
128     if (avpkt->size < 4 || avpkt->size - 4 > INT_MAX/8) {
129         av_log(avctx, AV_LOG_ERROR, "Invalid packet size\n");
130         return AVERROR_INVALIDDATA;
131     }
132 
133     /* Allocate buffer */
134     if ((ret = ff_thread_get_buffer(avctx, pic, 0)) < 0)
135         return ret;
136 
137     /* Set flags */
138     pic->key_frame = 1;
139     pic->pict_type = AV_PICTURE_TYPE_I;
140 
141     /* Version should always be 1 */
142     version = AV_RL32(src);
143 
144     if (version != 1)
145         av_log(avctx, AV_LOG_WARNING, "Unsupported VBLE Version: %d\n", version);
146 
147     init_get_bits(&gb, src + 4, (avpkt->size - 4) * 8);
148 
149     /* Unpack */
150     if (vble_unpack(ctx, &gb) < 0) {
151         av_log(avctx, AV_LOG_ERROR, "Invalid Code\n");
152         return AVERROR_INVALIDDATA;
153     }
154 
155     /* Restore planes. Should be almost identical to Huffyuv's. */
156     vble_restore_plane(ctx, pic, &gb, 0, offset, avctx->width, avctx->height);
157 
158     /* Chroma */
159     if (!(ctx->avctx->flags & AV_CODEC_FLAG_GRAY)) {
160         offset += avctx->width * avctx->height;
161         vble_restore_plane(ctx, pic, &gb, 1, offset, width_uv, height_uv);
162 
163         offset += width_uv * height_uv;
164         vble_restore_plane(ctx, pic, &gb, 2, offset, width_uv, height_uv);
165     }
166 
167     *got_frame       = 1;
168 
169     return avpkt->size;
170 }
171 
vble_decode_close(AVCodecContext *avctx)172 static av_cold int vble_decode_close(AVCodecContext *avctx)
173 {
174     VBLEContext *ctx = avctx->priv_data;
175     av_freep(&ctx->val);
176 
177     return 0;
178 }
179 
vble_decode_init(AVCodecContext *avctx)180 static av_cold int vble_decode_init(AVCodecContext *avctx)
181 {
182     VBLEContext *ctx = avctx->priv_data;
183 
184     /* Stash for later use */
185     ctx->avctx = avctx;
186     ff_llviddsp_init(&ctx->llviddsp);
187 
188     avctx->pix_fmt = AV_PIX_FMT_YUV420P;
189     avctx->bits_per_raw_sample = 8;
190 
191     ctx->size = av_image_get_buffer_size(avctx->pix_fmt,
192                                          avctx->width, avctx->height, 1);
193 
194     ctx->val = av_malloc_array(ctx->size, sizeof(*ctx->val));
195 
196     if (!ctx->val) {
197         av_log(avctx, AV_LOG_ERROR, "Could not allocate values buffer.\n");
198         return AVERROR(ENOMEM);
199     }
200 
201     return 0;
202 }
203 
204 const FFCodec ff_vble_decoder = {
205     .p.name         = "vble",
206     .p.long_name    = NULL_IF_CONFIG_SMALL("VBLE Lossless Codec"),
207     .p.type         = AVMEDIA_TYPE_VIDEO,
208     .p.id           = AV_CODEC_ID_VBLE,
209     .priv_data_size = sizeof(VBLEContext),
210     .init           = vble_decode_init,
211     .close          = vble_decode_close,
212     FF_CODEC_DECODE_CB(vble_decode_frame),
213     .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS,
214     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
215 };
216