2 * MPEG1 / MPEG2 video parser
3 * Copyright (c) 2000,2001 Fabrice Bellard
4 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
6 * This file is part of FFmpeg.
8 * FFmpeg 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.
13 * FFmpeg 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.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
27 struct MpvParseContext
{
29 AVRational frame_rate
;
30 int progressive_sequence
;
35 static void mpegvideo_extract_headers(AVCodecParserContext
*s
,
36 AVCodecContext
*avctx
,
37 const uint8_t *buf
, int buf_size
)
39 struct MpvParseContext
*pc
= s
->priv_data
;
40 const uint8_t *buf_end
= buf
+ buf_size
;
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
;
49 //FIXME replace the crap with get_bits()
52 while (buf
< buf_end
) {
54 buf
= avpriv_find_start_code(buf
, buf_end
, &start_code
);
55 bytes_left
= buf_end
- buf
;
57 case PICTURE_START_CODE
:
58 if (bytes_left
>= 2) {
59 s
->pict_type
= (buf
[1] >> 3) & 7;
61 vbv_delay
= ((buf
[1] & 0x07) << 13) | (buf
[2] << 5) | (buf
[3] >> 3);
65 if (bytes_left
>= 7) {
66 pc
->width
= (buf
[0] << 4) | (buf
[1] >> 4);
67 pc
->height
= ((buf
[1] & 0x0f) << 8) | buf
[2];
68 if(!avctx
->width
|| !avctx
->height
|| !avctx
->coded_width
|| !avctx
->coded_height
){
69 ff_set_dimensions(avctx
, pc
->width
, pc
->height
);
72 frame_rate_index
= buf
[3] & 0xf;
73 pc
->frame_rate
= avctx
->framerate
= ff_mpeg12_frame_rate_tab
[frame_rate_index
];
74 bit_rate
= (buf
[4]<<10) | (buf
[5]<<2) | (buf
[6]>>6);
75 avctx
->codec_id
= AV_CODEC_ID_MPEG1VIDEO
;
76 avctx
->ticks_per_frame
= 1;
80 if (bytes_left
>= 1) {
81 ext_type
= (buf
[0] >> 4);
83 case 0x1: /* sequence extension */
84 if (bytes_left
>= 6) {
85 horiz_size_ext
= ((buf
[1] & 1) << 1) | (buf
[2] >> 7);
86 vert_size_ext
= (buf
[2] >> 5) & 3;
87 bit_rate_ext
= ((buf
[2] & 0x1F)<<7) | (buf
[3]>>1);
88 frame_rate_ext_n
= (buf
[5] >> 5) & 3;
89 frame_rate_ext_d
= (buf
[5] & 0x1f);
90 pc
->progressive_sequence
= buf
[1] & (1 << 3);
91 avctx
->has_b_frames
= !(buf
[5] >> 7);
93 pc
->width
|=(horiz_size_ext
<< 12);
94 pc
->height
|=( vert_size_ext
<< 12);
95 bit_rate
= (bit_rate
&0x3FFFF) | (bit_rate_ext
<< 18);
97 ff_set_dimensions(avctx
, pc
->width
, pc
->height
);
98 avctx
->framerate
.num
= pc
->frame_rate
.num
* (frame_rate_ext_n
+ 1);
99 avctx
->framerate
.den
= pc
->frame_rate
.den
* (frame_rate_ext_d
+ 1);
100 avctx
->codec_id
= AV_CODEC_ID_MPEG2VIDEO
;
101 avctx
->ticks_per_frame
= 2;
104 case 0x8: /* picture coding extension */
105 if (bytes_left
>= 5) {
106 top_field_first
= buf
[3] & (1 << 7);
107 repeat_first_field
= buf
[3] & (1 << 1);
108 progressive_frame
= buf
[4] & (1 << 7);
110 /* check if we must repeat the frame */
112 if (repeat_first_field
) {
113 if (pc
->progressive_sequence
) {
118 } else if (progressive_frame
) {
123 if (!pc
->progressive_sequence
) {
125 s
->field_order
= AV_FIELD_TT
;
127 s
->field_order
= AV_FIELD_BB
;
129 s
->field_order
= AV_FIELD_PROGRESSIVE
;
138 /* we stop parsing when we encounter a slice. It ensures
139 that this function takes a negligible amount of time */
140 if (start_code
>= SLICE_MIN_START_CODE
&&
141 start_code
<= SLICE_MAX_START_CODE
)
147 if (avctx
->codec_id
== AV_CODEC_ID_MPEG2VIDEO
&& bit_rate
) {
148 avctx
->rc_max_rate
= 400*bit_rate
;
151 ((avctx
->codec_id
== AV_CODEC_ID_MPEG1VIDEO
&& bit_rate
!= 0x3FFFF) || vbv_delay
!= 0xFFFF)) {
152 avctx
->bit_rate
= 400*bit_rate
;
154 #if FF_API_AVCTX_TIMEBASE
155 if (avctx
->framerate
.num
)
156 avctx
->time_base
= av_inv_q(av_mul_q(avctx
->framerate
, (AVRational
){avctx
->ticks_per_frame
, 1}));
160 static int mpegvideo_parse(AVCodecParserContext
*s
,
161 AVCodecContext
*avctx
,
162 const uint8_t **poutbuf
, int *poutbuf_size
,
163 const uint8_t *buf
, int buf_size
)
165 struct MpvParseContext
*pc1
= s
->priv_data
;
166 ParseContext
*pc
= &pc1
->pc
;
169 if(s
->flags
& PARSER_FLAG_COMPLETE_FRAMES
){
172 next
= ff_mpeg1_find_frame_end(pc
, buf
, buf_size
, s
);
174 if (ff_combine_frame(pc
, next
, &buf
, &buf_size
) < 0) {
181 /* we have a full frame : we just parse the first few MPEG headers
182 to have the full timing information. The time take by this
183 function should be negligible for uncorrupted streams */
184 mpegvideo_extract_headers(s
, avctx
, buf
, buf_size
);
185 av_dlog(NULL
, "pict_type=%d frame_rate=%0.3f repeat_pict=%d\n",
186 s
->pict_type
, av_q2d(avctx
->framerate
), s
->repeat_pict
);
189 *poutbuf_size
= buf_size
;
193 static int mpegvideo_split(AVCodecContext
*avctx
,
194 const uint8_t *buf
, int buf_size
)
200 for(i
=0; i
<buf_size
; i
++){
201 state
= (state
<<8) | buf
[i
];
204 }else if(found
&& state
!= 0x1B5 && state
< 0x200 && state
>= 0x100)
210 static int mpegvideo_parse_init(AVCodecParserContext
*s
)
212 s
->pict_type
= AV_PICTURE_TYPE_NONE
; // first frame might be partial
216 AVCodecParser ff_mpegvideo_parser
= {
217 .codec_ids
= { AV_CODEC_ID_MPEG1VIDEO
, AV_CODEC_ID_MPEG2VIDEO
},
218 .priv_data_size
= sizeof(struct MpvParseContext
),
219 .parser_init
= mpegvideo_parse_init
,
220 .parser_parse
= mpegvideo_parse
,
221 .parser_close
= ff_parse_close
,
222 .split
= mpegvideo_split
,