3 * Copyright (c) 2004 Konstantin Shishkov
5 * This file is part of Libav.
7 * Libav 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.
12 * Libav 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.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
28 #include "bytestream.h"
30 typedef struct QpegContext{
31 AVCodecContext *avctx;
35 GetByteContext buffer;
38 static void qpeg_decode_intra(QpegContext *qctx, uint8_t *dst,
39 int stride, int width, int height)
50 dst = dst + height * stride;
52 while ((bytestream2_get_bytes_left(&qctx->buffer) > 0) && (rows_to_go > 0)) {
53 code = bytestream2_get_byte(&qctx->buffer);
55 if(code == 0xFC) /* end-of-picture code */
57 if(code >= 0xF8) { /* very long run */
58 c0 = bytestream2_get_byte(&qctx->buffer);
59 c1 = bytestream2_get_byte(&qctx->buffer);
60 run = ((code & 0x7) << 16) + (c0 << 8) + c1 + 2;
61 } else if (code >= 0xF0) { /* long run */
62 c0 = bytestream2_get_byte(&qctx->buffer);
63 run = ((code & 0xF) << 8) + c0 + 2;
64 } else if (code >= 0xE0) { /* short run */
65 run = (code & 0x1F) + 2;
66 } else if (code >= 0xC0) { /* very long copy */
67 c0 = bytestream2_get_byte(&qctx->buffer);
68 c1 = bytestream2_get_byte(&qctx->buffer);
69 copy = ((code & 0x3F) << 16) + (c0 << 8) + c1 + 1;
70 } else if (code >= 0x80) { /* long copy */
71 c0 = bytestream2_get_byte(&qctx->buffer);
72 copy = ((code & 0x7F) << 8) + c0 + 1;
73 } else { /* short copy */
77 /* perform actual run or copy */
81 p = bytestream2_get_byte(&qctx->buffer);
82 for(i = 0; i < run; i++) {
84 if (filled >= width) {
93 for(i = 0; i < copy; i++) {
94 dst[filled++] = bytestream2_get_byte(&qctx->buffer);
95 if (filled >= width) {
107 static const int qpeg_table_h[16] =
108 { 0x00, 0x20, 0x20, 0x20, 0x18, 0x10, 0x10, 0x20, 0x10, 0x08, 0x18, 0x08, 0x08, 0x18, 0x10, 0x04};
109 static const int qpeg_table_w[16] =
110 { 0x00, 0x20, 0x18, 0x08, 0x18, 0x10, 0x20, 0x10, 0x08, 0x10, 0x20, 0x20, 0x08, 0x10, 0x18, 0x04};
112 /* Decodes delta frames */
113 static void qpeg_decode_inter(QpegContext *qctx, uint8_t *dst,
114 int stride, int width, int height,
115 int delta, const uint8_t *ctable,
123 /* copy prev frame */
124 for(i = 0; i < height; i++)
125 memcpy(refdata + (i * width), dst + (i * stride), width);
127 orig_height = height;
129 dst = dst + height * stride;
131 while ((bytestream2_get_bytes_left(&qctx->buffer) > 0) && (height >= 0)) {
132 code = bytestream2_get_byte(&qctx->buffer);
135 /* motion compensation */
136 while((code & 0xF0) == 0xF0) {
139 int me_w, me_h, me_x, me_y;
143 /* get block size by index */
145 me_w = qpeg_table_w[me_idx];
146 me_h = qpeg_table_h[me_idx];
148 /* extract motion vector */
149 corr = bytestream2_get_byte(&qctx->buffer);
161 /* check motion vector */
162 if ((me_x + filled < 0) || (me_x + me_w + filled > width) ||
163 (height - me_y - me_h < 0) || (height - me_y > orig_height) ||
164 (filled + me_w > width) || (height - me_h < 0))
165 av_log(NULL, AV_LOG_ERROR, "Bogus motion vector (%i,%i), block size %ix%i at %i,%i\n",
166 me_x, me_y, me_w, me_h, filled, height);
168 /* do motion compensation */
169 me_plane = refdata + (filled + me_x) + (height - me_y) * width;
170 for(j = 0; j < me_h; j++) {
171 for(i = 0; i < me_w; i++)
172 dst[filled + i - (j * stride)] = me_plane[i - (j * width)];
176 code = bytestream2_get_byte(&qctx->buffer);
180 if(code == 0xE0) /* end-of-picture code */
182 if(code > 0xE0) { /* run code: 0xE1..0xFF */
186 p = bytestream2_get_byte(&qctx->buffer);
187 for(i = 0; i <= code; i++) {
189 if(filled >= width) {
195 } else if(code >= 0xC0) { /* copy code: 0xC0..0xDF */
198 for(i = 0; i <= code; i++) {
199 dst[filled++] = bytestream2_get_byte(&qctx->buffer);
200 if(filled >= width) {
206 } else if(code >= 0x80) { /* skip code: 0x80..0xBF */
210 /* codes 0x80 and 0x81 are actually escape codes,
211 skip value minus constant is in the next byte */
213 skip = bytestream2_get_byte(&qctx->buffer) + 64;
215 skip = bytestream2_get_byte(&qctx->buffer) + 320;
219 while( filled >= width) {
227 /* zero code treated as one-pixel skip */
229 dst[filled++] = ctable[code & 0x7F];
233 if(filled >= width) {
242 static int decode_frame(AVCodecContext *avctx,
243 void *data, int *data_size,
247 QpegContext * const a = avctx->priv_data;
248 AVFrame * const p = &a->pic;
251 const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
253 if (avpkt->size < 0x86) {
254 av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
255 return AVERROR_INVALIDDATA;
258 bytestream2_init(&a->buffer, avpkt->data, avpkt->size);
260 if (avctx->reget_buffer(avctx, p) < 0) {
261 av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
264 outdata = a->pic.data[0];
265 bytestream2_skip(&a->buffer, 4);
266 bytestream2_get_buffer(&a->buffer, ctable, 128);
267 bytestream2_skip(&a->buffer, 1);
269 delta = bytestream2_get_byte(&a->buffer);
271 qpeg_decode_intra(a, outdata, a->pic.linesize[0], avctx->width, avctx->height);
273 qpeg_decode_inter(a, outdata, a->pic.linesize[0], avctx->width, avctx->height, delta, ctable, a->refdata);
276 /* make the palette available on the way out */
278 a->pic.palette_has_changed = 1;
279 memcpy(a->pal, pal, AVPALETTE_SIZE);
281 memcpy(a->pic.data[1], a->pal, AVPALETTE_SIZE);
283 *data_size = sizeof(AVFrame);
284 *(AVFrame*)data = a->pic;
289 static av_cold int decode_init(AVCodecContext *avctx){
290 QpegContext * const a = avctx->priv_data;
293 avctx->pix_fmt= AV_PIX_FMT_PAL8;
294 a->refdata = av_malloc(avctx->width * avctx->height);
299 static av_cold int decode_end(AVCodecContext *avctx){
300 QpegContext * const a = avctx->priv_data;
301 AVFrame * const p = &a->pic;
304 avctx->release_buffer(avctx, p);
310 AVCodec ff_qpeg_decoder = {
312 .type = AVMEDIA_TYPE_VIDEO,
313 .id = AV_CODEC_ID_QPEG,
314 .priv_data_size = sizeof(QpegContext),
317 .decode = decode_frame,
318 .capabilities = CODEC_CAP_DR1,
319 .long_name = NULL_IF_CONFIG_SMALL("Q-team QPEG"),