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2ba45a60 DM |
1 | /* |
2 | * MxPEG clip file demuxer | |
3 | * Copyright (c) 2010 Anatoly Nenashev | |
4 | * | |
5 | * This file is part of FFmpeg. | |
6 | * | |
7 | * FFmpeg 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. | |
11 | * | |
12 | * FFmpeg 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. | |
16 | * | |
17 | * You should have received a copy of the GNU Lesser General Public | |
18 | * License along with FFmpeg; if not, write to the Free Software | |
19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
20 | */ | |
21 | ||
22 | #include "libavutil/channel_layout.h" | |
23 | #include "libavutil/internal.h" | |
24 | #include "libavutil/intreadwrite.h" | |
25 | #include "libavcodec/mjpeg.h" | |
26 | #include "avformat.h" | |
27 | #include "internal.h" | |
28 | #include "avio.h" | |
29 | ||
30 | #define DEFAULT_PACKET_SIZE 1024 | |
31 | #define OVERREAD_SIZE 3 | |
32 | ||
33 | typedef struct MXGContext { | |
34 | uint8_t *buffer; | |
35 | uint8_t *buffer_ptr; | |
36 | uint8_t *soi_ptr; | |
37 | unsigned int buffer_size; | |
38 | int64_t dts; | |
39 | unsigned int cache_size; | |
40 | } MXGContext; | |
41 | ||
42 | static int mxg_read_header(AVFormatContext *s) | |
43 | { | |
44 | AVStream *video_st, *audio_st; | |
45 | MXGContext *mxg = s->priv_data; | |
46 | ||
47 | /* video parameters will be extracted from the compressed bitstream */ | |
48 | video_st = avformat_new_stream(s, NULL); | |
49 | if (!video_st) | |
50 | return AVERROR(ENOMEM); | |
51 | video_st->codec->codec_type = AVMEDIA_TYPE_VIDEO; | |
52 | video_st->codec->codec_id = AV_CODEC_ID_MXPEG; | |
53 | avpriv_set_pts_info(video_st, 64, 1, 1000000); | |
54 | ||
55 | audio_st = avformat_new_stream(s, NULL); | |
56 | if (!audio_st) | |
57 | return AVERROR(ENOMEM); | |
58 | audio_st->codec->codec_type = AVMEDIA_TYPE_AUDIO; | |
59 | audio_st->codec->codec_id = AV_CODEC_ID_PCM_ALAW; | |
60 | audio_st->codec->channels = 1; | |
61 | audio_st->codec->channel_layout = AV_CH_LAYOUT_MONO; | |
62 | audio_st->codec->sample_rate = 8000; | |
63 | audio_st->codec->bits_per_coded_sample = 8; | |
64 | audio_st->codec->block_align = 1; | |
65 | avpriv_set_pts_info(audio_st, 64, 1, 1000000); | |
66 | ||
67 | mxg->soi_ptr = mxg->buffer_ptr = mxg->buffer = 0; | |
68 | mxg->buffer_size = 0; | |
69 | mxg->dts = AV_NOPTS_VALUE; | |
70 | mxg->cache_size = 0; | |
71 | ||
72 | return 0; | |
73 | } | |
74 | ||
75 | static uint8_t* mxg_find_startmarker(uint8_t *p, uint8_t *end) | |
76 | { | |
77 | for (; p < end - 3; p += 4) { | |
78 | uint32_t x = AV_RN32(p); | |
79 | ||
80 | if (x & (~(x+0x01010101)) & 0x80808080) { | |
81 | if (p[0] == 0xff) { | |
82 | return p; | |
83 | } else if (p[1] == 0xff) { | |
84 | return p+1; | |
85 | } else if (p[2] == 0xff) { | |
86 | return p+2; | |
87 | } else if (p[3] == 0xff) { | |
88 | return p+3; | |
89 | } | |
90 | } | |
91 | } | |
92 | ||
93 | for (; p < end; ++p) { | |
94 | if (*p == 0xff) return p; | |
95 | } | |
96 | ||
97 | return end; | |
98 | } | |
99 | ||
100 | static int mxg_update_cache(AVFormatContext *s, unsigned int cache_size) | |
101 | { | |
102 | MXGContext *mxg = s->priv_data; | |
103 | unsigned int current_pos = mxg->buffer_ptr - mxg->buffer; | |
104 | unsigned int soi_pos; | |
105 | uint8_t *buffer; | |
106 | int ret; | |
107 | ||
108 | /* reallocate internal buffer */ | |
109 | if (current_pos > current_pos + cache_size) | |
110 | return AVERROR(ENOMEM); | |
111 | soi_pos = mxg->soi_ptr - mxg->buffer; | |
112 | buffer = av_fast_realloc(mxg->buffer, &mxg->buffer_size, | |
113 | current_pos + cache_size + | |
114 | FF_INPUT_BUFFER_PADDING_SIZE); | |
115 | if (!buffer) | |
116 | return AVERROR(ENOMEM); | |
117 | mxg->buffer = buffer; | |
118 | mxg->buffer_ptr = mxg->buffer + current_pos; | |
119 | if (mxg->soi_ptr) mxg->soi_ptr = mxg->buffer + soi_pos; | |
120 | ||
121 | /* get data */ | |
122 | ret = avio_read(s->pb, mxg->buffer_ptr + mxg->cache_size, | |
123 | cache_size - mxg->cache_size); | |
124 | if (ret < 0) | |
125 | return ret; | |
126 | ||
127 | mxg->cache_size += ret; | |
128 | ||
129 | return ret; | |
130 | } | |
131 | ||
132 | static int mxg_read_packet(AVFormatContext *s, AVPacket *pkt) | |
133 | { | |
134 | int ret; | |
135 | unsigned int size; | |
136 | uint8_t *startmarker_ptr, *end, *search_end, marker; | |
137 | MXGContext *mxg = s->priv_data; | |
138 | ||
139 | while (!avio_feof(s->pb) && !s->pb->error){ | |
140 | if (mxg->cache_size <= OVERREAD_SIZE) { | |
141 | /* update internal buffer */ | |
142 | ret = mxg_update_cache(s, DEFAULT_PACKET_SIZE + OVERREAD_SIZE); | |
143 | if (ret < 0) | |
144 | return ret; | |
145 | } | |
146 | end = mxg->buffer_ptr + mxg->cache_size; | |
147 | ||
148 | /* find start marker - 0xff */ | |
149 | if (mxg->cache_size > OVERREAD_SIZE) { | |
150 | search_end = end - OVERREAD_SIZE; | |
151 | startmarker_ptr = mxg_find_startmarker(mxg->buffer_ptr, search_end); | |
152 | } else { | |
153 | search_end = end; | |
154 | startmarker_ptr = mxg_find_startmarker(mxg->buffer_ptr, search_end); | |
155 | if (startmarker_ptr >= search_end - 1 || | |
156 | *(startmarker_ptr + 1) != EOI) break; | |
157 | } | |
158 | ||
159 | if (startmarker_ptr != search_end) { /* start marker found */ | |
160 | marker = *(startmarker_ptr + 1); | |
161 | mxg->buffer_ptr = startmarker_ptr + 2; | |
162 | mxg->cache_size = end - mxg->buffer_ptr; | |
163 | ||
164 | if (marker == SOI) { | |
165 | mxg->soi_ptr = startmarker_ptr; | |
166 | } else if (marker == EOI) { | |
167 | if (!mxg->soi_ptr) { | |
168 | av_log(s, AV_LOG_WARNING, "Found EOI before SOI, skipping\n"); | |
169 | continue; | |
170 | } | |
171 | ||
172 | pkt->pts = pkt->dts = mxg->dts; | |
173 | pkt->stream_index = 0; | |
174 | #if FF_API_DESTRUCT_PACKET | |
175 | FF_DISABLE_DEPRECATION_WARNINGS | |
176 | pkt->destruct = NULL; | |
177 | FF_ENABLE_DEPRECATION_WARNINGS | |
178 | #endif | |
179 | pkt->buf = NULL; | |
180 | pkt->size = mxg->buffer_ptr - mxg->soi_ptr; | |
181 | pkt->data = mxg->soi_ptr; | |
182 | ||
183 | if (mxg->soi_ptr - mxg->buffer > mxg->cache_size) { | |
184 | if (mxg->cache_size > 0) { | |
185 | memcpy(mxg->buffer, mxg->buffer_ptr, mxg->cache_size); | |
186 | } | |
187 | ||
188 | mxg->buffer_ptr = mxg->buffer; | |
189 | } | |
190 | mxg->soi_ptr = 0; | |
191 | ||
192 | return pkt->size; | |
193 | } else if ( (SOF0 <= marker && marker <= SOF15) || | |
194 | (SOS <= marker && marker <= COM) ) { | |
195 | /* all other markers that start marker segment also contain | |
196 | length value (see specification for JPEG Annex B.1) */ | |
197 | size = AV_RB16(mxg->buffer_ptr); | |
198 | if (size < 2) | |
199 | return AVERROR(EINVAL); | |
200 | ||
201 | if (mxg->cache_size < size) { | |
202 | ret = mxg_update_cache(s, size); | |
203 | if (ret < 0) | |
204 | return ret; | |
205 | startmarker_ptr = mxg->buffer_ptr - 2; | |
206 | mxg->cache_size = 0; | |
207 | } else { | |
208 | mxg->cache_size -= size; | |
209 | } | |
210 | ||
211 | mxg->buffer_ptr += size; | |
212 | ||
213 | if (marker == APP13 && size >= 16) { /* audio data */ | |
214 | /* time (GMT) of first sample in usec since 1970, little-endian */ | |
215 | pkt->pts = pkt->dts = AV_RL64(startmarker_ptr + 8); | |
216 | pkt->stream_index = 1; | |
217 | #if FF_API_DESTRUCT_PACKET | |
218 | FF_DISABLE_DEPRECATION_WARNINGS | |
219 | pkt->destruct = NULL; | |
220 | FF_ENABLE_DEPRECATION_WARNINGS | |
221 | #endif | |
222 | pkt->buf = NULL; | |
223 | pkt->size = size - 14; | |
224 | pkt->data = startmarker_ptr + 16; | |
225 | ||
226 | if (startmarker_ptr - mxg->buffer > mxg->cache_size) { | |
227 | if (mxg->cache_size > 0) { | |
228 | memcpy(mxg->buffer, mxg->buffer_ptr, mxg->cache_size); | |
229 | } | |
230 | mxg->buffer_ptr = mxg->buffer; | |
231 | } | |
232 | ||
233 | return pkt->size; | |
234 | } else if (marker == COM && size >= 18 && | |
235 | !strncmp(startmarker_ptr + 4, "MXF", 3)) { | |
236 | /* time (GMT) of video frame in usec since 1970, little-endian */ | |
237 | mxg->dts = AV_RL64(startmarker_ptr + 12); | |
238 | } | |
239 | } | |
240 | } else { | |
241 | /* start marker not found */ | |
242 | mxg->buffer_ptr = search_end; | |
243 | mxg->cache_size = OVERREAD_SIZE; | |
244 | } | |
245 | } | |
246 | ||
247 | return AVERROR_EOF; | |
248 | } | |
249 | ||
250 | static int mxg_close(struct AVFormatContext *s) | |
251 | { | |
252 | MXGContext *mxg = s->priv_data; | |
253 | av_freep(&mxg->buffer); | |
254 | return 0; | |
255 | } | |
256 | ||
257 | AVInputFormat ff_mxg_demuxer = { | |
258 | .name = "mxg", | |
259 | .long_name = NULL_IF_CONFIG_SMALL("MxPEG clip"), | |
260 | .priv_data_size = sizeof(MXGContext), | |
261 | .read_header = mxg_read_header, | |
262 | .read_packet = mxg_read_packet, | |
263 | .read_close = mxg_close, | |
264 | .extensions = "mxg", | |
265 | }; |