| 1 | /* |
| 2 | * MPEG4 Video frame extraction |
| 3 | * Copyright (c) 2003 Fabrice Bellard |
| 4 | * Copyright (c) 2003 Michael Niedermayer |
| 5 | * |
| 6 | * This file is part of FFmpeg. |
| 7 | * |
| 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. |
| 12 | * |
| 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. |
| 17 | * |
| 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 |
| 21 | */ |
| 22 | |
| 23 | #define UNCHECKED_BITSTREAM_READER 1 |
| 24 | |
| 25 | #include "internal.h" |
| 26 | #include "parser.h" |
| 27 | #include "mpegvideo.h" |
| 28 | #include "mpeg4video.h" |
| 29 | #include "mpeg4video_parser.h" |
| 30 | |
| 31 | struct Mp4vParseContext { |
| 32 | ParseContext pc; |
| 33 | Mpeg4DecContext dec_ctx; |
| 34 | int first_picture; |
| 35 | }; |
| 36 | |
| 37 | int ff_mpeg4_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size) |
| 38 | { |
| 39 | int vop_found, i; |
| 40 | uint32_t state; |
| 41 | |
| 42 | vop_found = pc->frame_start_found; |
| 43 | state = pc->state; |
| 44 | |
| 45 | i = 0; |
| 46 | if (!vop_found) { |
| 47 | for (i = 0; i < buf_size; i++) { |
| 48 | state = (state << 8) | buf[i]; |
| 49 | if (state == 0x1B6) { |
| 50 | i++; |
| 51 | vop_found = 1; |
| 52 | break; |
| 53 | } |
| 54 | } |
| 55 | } |
| 56 | |
| 57 | if (vop_found) { |
| 58 | /* EOF considered as end of frame */ |
| 59 | if (buf_size == 0) |
| 60 | return 0; |
| 61 | for (; i < buf_size; i++) { |
| 62 | state = (state << 8) | buf[i]; |
| 63 | if ((state & 0xFFFFFF00) == 0x100) { |
| 64 | pc->frame_start_found = 0; |
| 65 | pc->state = -1; |
| 66 | return i - 3; |
| 67 | } |
| 68 | } |
| 69 | } |
| 70 | pc->frame_start_found = vop_found; |
| 71 | pc->state = state; |
| 72 | return END_NOT_FOUND; |
| 73 | } |
| 74 | |
| 75 | /* XXX: make it use less memory */ |
| 76 | static int mpeg4_decode_header(AVCodecParserContext *s1, AVCodecContext *avctx, |
| 77 | const uint8_t *buf, int buf_size) |
| 78 | { |
| 79 | struct Mp4vParseContext *pc = s1->priv_data; |
| 80 | Mpeg4DecContext *dec_ctx = &pc->dec_ctx; |
| 81 | MpegEncContext *s = &dec_ctx->m; |
| 82 | GetBitContext gb1, *gb = &gb1; |
| 83 | int ret; |
| 84 | |
| 85 | s->avctx = avctx; |
| 86 | s->current_picture_ptr = &s->current_picture; |
| 87 | |
| 88 | if (avctx->extradata_size && pc->first_picture) { |
| 89 | init_get_bits(gb, avctx->extradata, avctx->extradata_size * 8); |
| 90 | ret = ff_mpeg4_decode_picture_header(dec_ctx, gb); |
| 91 | if (ret < 0) |
| 92 | av_log(avctx, AV_LOG_WARNING, "Failed to parse extradata\n"); |
| 93 | } |
| 94 | |
| 95 | init_get_bits(gb, buf, 8 * buf_size); |
| 96 | ret = ff_mpeg4_decode_picture_header(dec_ctx, gb); |
| 97 | if (s->width && (!avctx->width || !avctx->height || |
| 98 | !avctx->coded_width || !avctx->coded_height)) { |
| 99 | ret = ff_set_dimensions(avctx, s->width, s->height); |
| 100 | if (ret < 0) |
| 101 | return ret; |
| 102 | } |
| 103 | if((s1->flags & PARSER_FLAG_USE_CODEC_TS) && s->avctx->time_base.den>0 && ret>=0){ |
| 104 | av_assert1(s1->pts == AV_NOPTS_VALUE); |
| 105 | av_assert1(s1->dts == AV_NOPTS_VALUE); |
| 106 | |
| 107 | s1->pts = av_rescale_q(s->time, (AVRational){1, s->avctx->time_base.den}, (AVRational){1, 1200000}); |
| 108 | } |
| 109 | |
| 110 | s1->pict_type = s->pict_type; |
| 111 | pc->first_picture = 0; |
| 112 | return ret; |
| 113 | } |
| 114 | |
| 115 | static av_cold int mpeg4video_parse_init(AVCodecParserContext *s) |
| 116 | { |
| 117 | struct Mp4vParseContext *pc = s->priv_data; |
| 118 | |
| 119 | ff_mpeg4videodec_static_init(); |
| 120 | |
| 121 | pc->first_picture = 1; |
| 122 | pc->dec_ctx.m.quant_precision = 5; |
| 123 | pc->dec_ctx.m.slice_context_count = 1; |
| 124 | pc->dec_ctx.showed_packed_warning = 1; |
| 125 | return 0; |
| 126 | } |
| 127 | |
| 128 | static int mpeg4video_parse(AVCodecParserContext *s, |
| 129 | AVCodecContext *avctx, |
| 130 | const uint8_t **poutbuf, int *poutbuf_size, |
| 131 | const uint8_t *buf, int buf_size) |
| 132 | { |
| 133 | ParseContext *pc = s->priv_data; |
| 134 | int next; |
| 135 | |
| 136 | if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) { |
| 137 | next = buf_size; |
| 138 | } else { |
| 139 | next = ff_mpeg4_find_frame_end(pc, buf, buf_size); |
| 140 | |
| 141 | if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) { |
| 142 | *poutbuf = NULL; |
| 143 | *poutbuf_size = 0; |
| 144 | return buf_size; |
| 145 | } |
| 146 | } |
| 147 | mpeg4_decode_header(s, avctx, buf, buf_size); |
| 148 | |
| 149 | *poutbuf = buf; |
| 150 | *poutbuf_size = buf_size; |
| 151 | return next; |
| 152 | } |
| 153 | |
| 154 | AVCodecParser ff_mpeg4video_parser = { |
| 155 | .codec_ids = { AV_CODEC_ID_MPEG4 }, |
| 156 | .priv_data_size = sizeof(struct Mp4vParseContext), |
| 157 | .parser_init = mpeg4video_parse_init, |
| 158 | .parser_parse = mpeg4video_parse, |
| 159 | .parser_close = ff_parse_close, |
| 160 | .split = ff_mpeg4video_split, |
| 161 | }; |