mpegvideo: Return correct coded frame sizes from parser
[libav.git] / libavcodec / mpegvideo_parser.c
1 /*
2 * MPEG-1 / MPEG-2 video parser
3 * Copyright (c) 2000,2001 Fabrice Bellard
4 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
5 *
6 * This file is part of Libav.
7 *
8 * Libav 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 * Libav 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 Libav; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 #include "parser.h"
24 #include "mpeg12.h"
25 #include "internal.h"
26
27 struct MpvParseContext {
28 ParseContext pc;
29 AVRational frame_rate;
30 int progressive_sequence;
31 int width, height;
32 };
33
34
35 static void mpegvideo_extract_headers(AVCodecParserContext *s,
36 AVCodecContext *avctx,
37 const uint8_t *buf, int buf_size)
38 {
39 struct MpvParseContext *pc = s->priv_data;
40 const uint8_t *buf_end = buf + buf_size;
41 uint32_t start_code;
42 int frame_rate_index, ext_type, bytes_left;
43 int frame_rate_ext_n, frame_rate_ext_d;
44 int top_field_first, repeat_first_field, progressive_frame;
45 int horiz_size_ext, vert_size_ext, bit_rate_ext;
46 int did_set_size=0;
47 int chroma_format;
48 enum AVPixelFormat pix_fmt = AV_PIX_FMT_NONE;
49 //FIXME replace the crap with get_bits()
50 s->repeat_pict = 0;
51
52 while (buf < buf_end) {
53 start_code= -1;
54 buf= avpriv_find_start_code(buf, buf_end, &start_code);
55 bytes_left = buf_end - buf;
56 switch(start_code) {
57 case PICTURE_START_CODE:
58 if (bytes_left >= 2) {
59 s->pict_type = (buf[1] >> 3) & 7;
60 }
61 break;
62 case SEQ_START_CODE:
63 if (bytes_left >= 7) {
64 pc->width = (buf[0] << 4) | (buf[1] >> 4);
65 pc->height = ((buf[1] & 0x0f) << 8) | buf[2];
66 if(!avctx->width || !avctx->height || !avctx->coded_width || !avctx->coded_height){
67 ff_set_dimensions(avctx, pc->width, pc->height);
68 did_set_size=1;
69 }
70 pix_fmt = AV_PIX_FMT_YUV420P;
71 frame_rate_index = buf[3] & 0xf;
72 pc->frame_rate = avctx->framerate = ff_mpeg12_frame_rate_tab[frame_rate_index];
73 avctx->bit_rate = ((buf[4]<<10) | (buf[5]<<2) | (buf[6]>>6))*400;
74 avctx->codec_id = AV_CODEC_ID_MPEG1VIDEO;
75 }
76 break;
77 case EXT_START_CODE:
78 if (bytes_left >= 1) {
79 ext_type = (buf[0] >> 4);
80 switch(ext_type) {
81 case 0x1: /* sequence extension */
82 if (bytes_left >= 6) {
83 horiz_size_ext = ((buf[1] & 1) << 1) | (buf[2] >> 7);
84 vert_size_ext = (buf[2] >> 5) & 3;
85 bit_rate_ext = ((buf[2] & 0x1F)<<7) | (buf[3]>>1);
86 frame_rate_ext_n = (buf[5] >> 5) & 3;
87 frame_rate_ext_d = (buf[5] & 0x1f);
88 pc->progressive_sequence = buf[1] & (1 << 3);
89 avctx->has_b_frames= !(buf[5] >> 7);
90
91 chroma_format = (buf[1] >> 1) & 3;
92 switch (chroma_format) {
93 case 1: pix_fmt = AV_PIX_FMT_YUV420P; break;
94 case 2: pix_fmt = AV_PIX_FMT_YUV422P; break;
95 case 3: pix_fmt = AV_PIX_FMT_YUV444P; break;
96 }
97
98 pc->width |=(horiz_size_ext << 12);
99 pc->height |=( vert_size_ext << 12);
100 avctx->bit_rate += (bit_rate_ext << 18) * 400;
101 if(did_set_size)
102 ff_set_dimensions(avctx, pc->width, pc->height);
103 avctx->framerate.num = pc->frame_rate.num * (frame_rate_ext_n + 1) * 2;
104 avctx->framerate.den = pc->frame_rate.den * (frame_rate_ext_d + 1);
105 avctx->codec_id = AV_CODEC_ID_MPEG2VIDEO;
106 }
107 break;
108 case 0x8: /* picture coding extension */
109 if (bytes_left >= 5) {
110 top_field_first = buf[3] & (1 << 7);
111 repeat_first_field = buf[3] & (1 << 1);
112 progressive_frame = buf[4] & (1 << 7);
113
114 /* check if we must repeat the frame */
115 s->repeat_pict = 1;
116 if (repeat_first_field) {
117 if (pc->progressive_sequence) {
118 if (top_field_first)
119 s->repeat_pict = 5;
120 else
121 s->repeat_pict = 3;
122 } else if (progressive_frame) {
123 s->repeat_pict = 2;
124 }
125 }
126
127 if (!pc->progressive_sequence) {
128 if (top_field_first)
129 s->field_order = AV_FIELD_TT;
130 else
131 s->field_order = AV_FIELD_BB;
132 } else
133 s->field_order = AV_FIELD_PROGRESSIVE;
134 }
135 break;
136 }
137 }
138 break;
139 case -1:
140 goto the_end;
141 default:
142 /* we stop parsing when we encounter a slice. It ensures
143 that this function takes a negligible amount of time */
144 if (start_code >= SLICE_MIN_START_CODE &&
145 start_code <= SLICE_MAX_START_CODE)
146 goto the_end;
147 break;
148 }
149 }
150 the_end: ;
151
152 if (pix_fmt != AV_PIX_FMT_NONE) {
153 s->format = pix_fmt;
154 s->width = pc->width;
155 s->height = pc->height;
156 s->coded_width = FFALIGN(pc->width, 16);
157 s->coded_height = FFALIGN(pc->height, 16);
158 }
159
160 #if FF_API_AVCTX_TIMEBASE
161 if (avctx->framerate.num)
162 avctx->time_base = av_inv_q(avctx->framerate);
163 #endif
164 }
165
166 static int mpegvideo_parse(AVCodecParserContext *s,
167 AVCodecContext *avctx,
168 const uint8_t **poutbuf, int *poutbuf_size,
169 const uint8_t *buf, int buf_size)
170 {
171 struct MpvParseContext *pc1 = s->priv_data;
172 ParseContext *pc= &pc1->pc;
173 int next;
174
175 if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
176 next= buf_size;
177 }else{
178 next= ff_mpeg1_find_frame_end(pc, buf, buf_size, s);
179
180 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
181 *poutbuf = NULL;
182 *poutbuf_size = 0;
183 return buf_size;
184 }
185
186 }
187 /* we have a full frame : we just parse the first few MPEG headers
188 to have the full timing information. The time take by this
189 function should be negligible for uncorrupted streams */
190 mpegvideo_extract_headers(s, avctx, buf, buf_size);
191 ff_dlog(NULL, "pict_type=%d frame_rate=%0.3f repeat_pict=%d\n",
192 s->pict_type, (double)avctx->time_base.den / avctx->time_base.num, s->repeat_pict);
193
194 *poutbuf = buf;
195 *poutbuf_size = buf_size;
196 return next;
197 }
198
199 static int mpegvideo_split(AVCodecContext *avctx,
200 const uint8_t *buf, int buf_size)
201 {
202 int i;
203 uint32_t state= -1;
204
205 for(i=0; i<buf_size; i++){
206 state= (state<<8) | buf[i];
207 if(state != 0x1B3 && state != 0x1B5 && state < 0x200 && state >= 0x100)
208 return i-3;
209 }
210 return 0;
211 }
212
213 AVCodecParser ff_mpegvideo_parser = {
214 .codec_ids = { AV_CODEC_ID_MPEG1VIDEO, AV_CODEC_ID_MPEG2VIDEO },
215 .priv_data_size = sizeof(struct MpvParseContext),
216 .parser_parse = mpegvideo_parse,
217 .parser_close = ff_parse_close,
218 .split = mpegvideo_split,
219 };