| 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 | }; |