1 /*
2 * CPiA video decoder.
3 * Copyright (c) 2010 Hans de Goede <hdegoede@redhat.com>
4 *
5 * This decoder is based on the LGPL code available at
6 * https://v4l4j.googlecode.com/svn/v4l4j/trunk/libvideo/libv4lconvert/cpia1.c
7 *
8 * This file is part of FFmpeg.
9 *
10 * FFmpeg is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU Lesser General Public
12 * License as published by the Free Software Foundation; either
13 * version 2.1 of the License, or (at your option) any later version.
14 *
15 * FFmpeg is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * Lesser General Public License for more details.
19 *
20 * You should have received a copy of the GNU Lesser General Public
21 * License along with FFmpeg; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 */
24
25 #include "avcodec.h"
26 #include "codec_internal.h"
27 #include "get_bits.h"
28 #include "internal.h"
29
30
31 #define FRAME_HEADER_SIZE 64
32 #define MAGIC_0 0x19 /**< First header byte */
33 #define MAGIC_1 0x68 /**< Second header byte */
34 #define SUBSAMPLE_420 0
35 #define SUBSAMPLE_422 1
36 #define YUVORDER_YUYV 0
37 #define YUVORDER_UYVY 1
38 #define NOT_COMPRESSED 0
39 #define COMPRESSED 1
40 #define NO_DECIMATION 0
41 #define DECIMATION_ENAB 1
42 #define EOL 0xfd /**< End Of Line marker */
43 #define EOI 0xff /**< End Of Image marker */
44
45
46 typedef struct {
47 AVFrame *frame;
48 } CpiaContext;
49
50
cpia_decode_frame(AVCodecContext * avctx,AVFrame * rframe,int * got_frame,AVPacket * avpkt)51 static int cpia_decode_frame(AVCodecContext *avctx, AVFrame *rframe,
52 int *got_frame, AVPacket* avpkt)
53 {
54 CpiaContext* const cpia = avctx->priv_data;
55 int i,j,ret;
56
57 const uint8_t *const header = avpkt->data;
58 const uint8_t *src;
59 int src_size;
60 uint16_t linelength;
61 uint8_t skip;
62
63 AVFrame *frame = cpia->frame;
64 uint8_t *y, *u, *v, *y_end, *u_end, *v_end;
65
66 // Check header
67 if ( avpkt->size < FRAME_HEADER_SIZE + avctx->height * 3
68 || header[0] != MAGIC_0 || header[1] != MAGIC_1
69 || (header[17] != SUBSAMPLE_420 && header[17] != SUBSAMPLE_422)
70 || (header[18] != YUVORDER_YUYV && header[18] != YUVORDER_UYVY)
71 || (header[28] != NOT_COMPRESSED && header[28] != COMPRESSED)
72 || (header[29] != NO_DECIMATION && header[29] != DECIMATION_ENAB)
73 ) {
74 av_log(avctx, AV_LOG_ERROR, "Invalid header!\n");
75 return AVERROR_INVALIDDATA;
76 }
77
78 // currently unsupported properties
79 if (header[17] == SUBSAMPLE_422) {
80 avpriv_report_missing_feature(avctx, "4:2:2 subsampling");
81 return AVERROR_PATCHWELCOME;
82 }
83 if (header[18] == YUVORDER_UYVY) {
84 avpriv_report_missing_feature(avctx, "YUV byte order UYVY");
85 return AVERROR_PATCHWELCOME;
86 }
87 if (header[29] == DECIMATION_ENAB) {
88 avpriv_report_missing_feature(avctx, "Decimation");
89 return AVERROR_PATCHWELCOME;
90 }
91
92 src = header + FRAME_HEADER_SIZE;
93 src_size = avpkt->size - FRAME_HEADER_SIZE;
94
95 if (header[28] == NOT_COMPRESSED) {
96 frame->pict_type = AV_PICTURE_TYPE_I;
97 frame->key_frame = 1;
98 } else {
99 frame->pict_type = AV_PICTURE_TYPE_P;
100 frame->key_frame = 0;
101 }
102
103 // Get buffer filled with previous frame
104 if ((ret = ff_reget_buffer(avctx, frame, 0)) < 0)
105 return ret;
106
107
108 for ( i = 0;
109 i < frame->height;
110 i++, src += linelength, src_size -= linelength
111 ) {
112 // Read line length, two byte little endian
113 linelength = AV_RL16(src);
114 src += 2;
115 src_size -= 2;
116
117 if (src_size < linelength) {
118 frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM;
119 av_log(avctx, AV_LOG_WARNING, "Frame ended unexpectedly!\n");
120 break;
121 }
122 if (src[linelength - 1] != EOL) {
123 frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM;
124 av_log(avctx, AV_LOG_WARNING, "Wrong line length %d or line not terminated properly (found 0x%02x)!\n", linelength, src[linelength - 1]);
125 break;
126 }
127
128 /* Update the data pointers. Y data is on every line.
129 * U and V data on every second line
130 */
131 y = &frame->data[0][i * frame->linesize[0]];
132 u = &frame->data[1][(i >> 1) * frame->linesize[1]];
133 v = &frame->data[2][(i >> 1) * frame->linesize[2]];
134 y_end = y + frame->linesize[0] - 1;
135 u_end = u + frame->linesize[1] - 1;
136 v_end = v + frame->linesize[2] - 1;
137
138 if ((i & 1) && header[17] == SUBSAMPLE_420) {
139 /* We are on an odd line and 420 subsample is used.
140 * On this line only Y values are specified, one per pixel.
141 */
142 for (j = 0; j < linelength - 1; j++) {
143 if (y > y_end) {
144 frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM;
145 av_log(avctx, AV_LOG_WARNING, "Decoded data exceeded linesize!\n");
146 break;
147 }
148 if ((src[j] & 1) && header[28] == COMPRESSED) {
149 /* It seems that odd lines are always uncompressed, but
150 * we do it according to specification anyways.
151 */
152 skip = src[j] >> 1;
153 y += skip;
154 } else {
155 *(y++) = src[j];
156 }
157 }
158 } else if (header[17] == SUBSAMPLE_420) {
159 /* We are on an even line and 420 subsample is used.
160 * On this line each pair of pixels is described by four bytes.
161 */
162 for (j = 0; j < linelength - 4; ) {
163 if (y + 1 > y_end || u > u_end || v > v_end) {
164 frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM;
165 av_log(avctx, AV_LOG_WARNING, "Decoded data exceeded linesize!\n");
166 break;
167 }
168 if ((src[j] & 1) && header[28] == COMPRESSED) {
169 // Skip amount of pixels and move forward one byte
170 skip = src[j] >> 1;
171 y += skip;
172 u += skip >> 1;
173 v += skip >> 1;
174 j++;
175 } else {
176 // Set image data as specified and move forward 4 bytes
177 *(y++) = src[j];
178 *(u++) = src[j+1];
179 *(y++) = src[j+2];
180 *(v++) = src[j+3];
181 j += 4;
182 }
183 }
184 }
185 }
186
187 *got_frame = 1;
188 if ((ret = av_frame_ref(rframe, cpia->frame)) < 0)
189 return ret;
190
191 return avpkt->size;
192 }
193
cpia_decode_init(AVCodecContext * avctx)194 static av_cold int cpia_decode_init(AVCodecContext *avctx)
195 {
196 CpiaContext *s = avctx->priv_data;
197
198 // output pixel format
199 avctx->pix_fmt = AV_PIX_FMT_YUV420P;
200
201 /* The default timebase set by the v4l2 demuxer leads to probing which is buggy.
202 * Set some reasonable time_base to skip this.
203 */
204 if (avctx->time_base.num == 1 && avctx->time_base.den == 1000000) {
205 avctx->time_base.num = 1;
206 avctx->time_base.den = 60;
207 }
208
209 s->frame = av_frame_alloc();
210 if (!s->frame)
211 return AVERROR(ENOMEM);
212
213 return 0;
214 }
215
cpia_decode_end(AVCodecContext * avctx)216 static av_cold int cpia_decode_end(AVCodecContext *avctx)
217 {
218 CpiaContext *s = avctx->priv_data;
219
220 av_frame_free(&s->frame);
221
222 return 0;
223 }
224
225 const FFCodec ff_cpia_decoder = {
226 .p.name = "cpia",
227 .p.long_name = NULL_IF_CONFIG_SMALL("CPiA video format"),
228 .p.type = AVMEDIA_TYPE_VIDEO,
229 .p.id = AV_CODEC_ID_CPIA,
230 .priv_data_size = sizeof(CpiaContext),
231 .init = cpia_decode_init,
232 .close = cpia_decode_end,
233 FF_CODEC_DECODE_CB(cpia_decode_frame),
234 .p.capabilities = AV_CODEC_CAP_DR1,
235 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
236 };
237