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 "get_bits.h"
27 #include "internal.h"
28
29
30 #define FRAME_HEADER_SIZE 64
31 #define MAGIC_0 0x19 /**< First header byte */
32 #define MAGIC_1 0x68 /**< Second header byte */
33 #define SUBSAMPLE_420 0
34 #define SUBSAMPLE_422 1
35 #define YUVORDER_YUYV 0
36 #define YUVORDER_UYVY 1
37 #define NOT_COMPRESSED 0
38 #define COMPRESSED 1
39 #define NO_DECIMATION 0
40 #define DECIMATION_ENAB 1
41 #define EOL 0xfd /**< End Of Line marker */
42 #define EOI 0xff /**< End Of Image marker */
43
44
45 typedef struct {
46 AVFrame *frame;
47 } CpiaContext;
48
49
cpia_decode_frame(AVCodecContext * avctx,void * data,int * got_frame,AVPacket * avpkt)50 static int cpia_decode_frame(AVCodecContext *avctx,
51 void *data, int *got_frame, AVPacket* avpkt)
52 {
53 CpiaContext* const cpia = avctx->priv_data;
54 int i,j,ret;
55
56 uint8_t* const header = avpkt->data;
57 uint8_t* src;
58 int src_size;
59 uint16_t linelength;
60 uint8_t skip;
61
62 AVFrame *frame = cpia->frame;
63 uint8_t *y, *u, *v, *y_end, *u_end, *v_end;
64
65 // Check header
66 if ( avpkt->size < FRAME_HEADER_SIZE + avctx->height * 3
67 || header[0] != MAGIC_0 || header[1] != MAGIC_1
68 || (header[17] != SUBSAMPLE_420 && header[17] != SUBSAMPLE_422)
69 || (header[18] != YUVORDER_YUYV && header[18] != YUVORDER_UYVY)
70 || (header[28] != NOT_COMPRESSED && header[28] != COMPRESSED)
71 || (header[29] != NO_DECIMATION && header[29] != DECIMATION_ENAB)
72 ) {
73 av_log(avctx, AV_LOG_ERROR, "Invalid header!\n");
74 return AVERROR_INVALIDDATA;
75 }
76
77 // currently unsupported properties
78 if (header[17] == SUBSAMPLE_422) {
79 avpriv_report_missing_feature(avctx, "4:2:2 subsampling");
80 return AVERROR_PATCHWELCOME;
81 }
82 if (header[18] == YUVORDER_UYVY) {
83 avpriv_report_missing_feature(avctx, "YUV byte order UYVY");
84 return AVERROR_PATCHWELCOME;
85 }
86 if (header[29] == DECIMATION_ENAB) {
87 avpriv_report_missing_feature(avctx, "Decimation");
88 return AVERROR_PATCHWELCOME;
89 }
90
91 src = header + FRAME_HEADER_SIZE;
92 src_size = avpkt->size - FRAME_HEADER_SIZE;
93
94 if (header[28] == NOT_COMPRESSED) {
95 frame->pict_type = AV_PICTURE_TYPE_I;
96 frame->key_frame = 1;
97 } else {
98 frame->pict_type = AV_PICTURE_TYPE_P;
99 frame->key_frame = 0;
100 }
101
102 // Get buffer filled with previous frame
103 if ((ret = ff_reget_buffer(avctx, frame, 0)) < 0)
104 return ret;
105
106
107 for ( i = 0;
108 i < frame->height;
109 i++, src += linelength, src_size -= linelength
110 ) {
111 // Read line length, two byte little endian
112 linelength = AV_RL16(src);
113 src += 2;
114 src_size -= 2;
115
116 if (src_size < linelength) {
117 frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM;
118 av_log(avctx, AV_LOG_WARNING, "Frame ended unexpectedly!\n");
119 break;
120 }
121 if (src[linelength - 1] != EOL) {
122 frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM;
123 av_log(avctx, AV_LOG_WARNING, "Wrong line length %d or line not terminated properly (found 0x%02x)!\n", linelength, src[linelength - 1]);
124 break;
125 }
126
127 /* Update the data pointers. Y data is on every line.
128 * U and V data on every second line
129 */
130 y = &frame->data[0][i * frame->linesize[0]];
131 u = &frame->data[1][(i >> 1) * frame->linesize[1]];
132 v = &frame->data[2][(i >> 1) * frame->linesize[2]];
133 y_end = y + frame->linesize[0] - 1;
134 u_end = u + frame->linesize[1] - 1;
135 v_end = v + frame->linesize[2] - 1;
136
137 if ((i & 1) && header[17] == SUBSAMPLE_420) {
138 /* We are on an odd line and 420 subsample is used.
139 * On this line only Y values are specified, one per pixel.
140 */
141 for (j = 0; j < linelength - 1; j++) {
142 if (y > y_end) {
143 frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM;
144 av_log(avctx, AV_LOG_WARNING, "Decoded data exceeded linesize!\n");
145 break;
146 }
147 if ((src[j] & 1) && header[28] == COMPRESSED) {
148 /* It seems that odd lines are always uncompressed, but
149 * we do it according to specification anyways.
150 */
151 skip = src[j] >> 1;
152 y += skip;
153 } else {
154 *(y++) = src[j];
155 }
156 }
157 } else if (header[17] == SUBSAMPLE_420) {
158 /* We are on an even line and 420 subsample is used.
159 * On this line each pair of pixels is described by four bytes.
160 */
161 for (j = 0; j < linelength - 4; ) {
162 if (y + 1 > y_end || u > u_end || v > v_end) {
163 frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM;
164 av_log(avctx, AV_LOG_WARNING, "Decoded data exceeded linesize!\n");
165 break;
166 }
167 if ((src[j] & 1) && header[28] == COMPRESSED) {
168 // Skip amount of pixels and move forward one byte
169 skip = src[j] >> 1;
170 y += skip;
171 u += skip >> 1;
172 v += skip >> 1;
173 j++;
174 } else {
175 // Set image data as specified and move forward 4 bytes
176 *(y++) = src[j];
177 *(u++) = src[j+1];
178 *(y++) = src[j+2];
179 *(v++) = src[j+3];
180 j += 4;
181 }
182 }
183 }
184 }
185
186 *got_frame = 1;
187 if ((ret = av_frame_ref(data, cpia->frame)) < 0)
188 return ret;
189
190 return avpkt->size;
191 }
192
cpia_decode_init(AVCodecContext * avctx)193 static av_cold int cpia_decode_init(AVCodecContext *avctx)
194 {
195 CpiaContext *s = avctx->priv_data;
196
197 // output pixel format
198 avctx->pix_fmt = AV_PIX_FMT_YUV420P;
199
200 /* The default timebase set by the v4l2 demuxer leads to probing which is buggy.
201 * Set some reasonable time_base to skip this.
202 */
203 if (avctx->time_base.num == 1 && avctx->time_base.den == 1000000) {
204 avctx->time_base.num = 1;
205 avctx->time_base.den = 60;
206 }
207
208 s->frame = av_frame_alloc();
209 if (!s->frame)
210 return AVERROR(ENOMEM);
211
212 return 0;
213 }
214
cpia_decode_end(AVCodecContext * avctx)215 static av_cold int cpia_decode_end(AVCodecContext *avctx)
216 {
217 CpiaContext *s = avctx->priv_data;
218
219 av_frame_free(&s->frame);
220
221 return 0;
222 }
223
224 AVCodec ff_cpia_decoder = {
225 .name = "cpia",
226 .long_name = NULL_IF_CONFIG_SMALL("CPiA video format"),
227 .type = AVMEDIA_TYPE_VIDEO,
228 .id = AV_CODEC_ID_CPIA,
229 .priv_data_size = sizeof(CpiaContext),
230 .init = cpia_decode_init,
231 .close = cpia_decode_end,
232 .decode = cpia_decode_frame,
233 .capabilities = AV_CODEC_CAP_DR1,
234 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
235 };
236