| /* | |
| * MxPEG clip file demuxer | |
| * Copyright (c) 2010 Anatoly Nenashev | |
| * | |
| * This file is part of FFmpeg. | |
| * | |
| * FFmpeg is free software; you can redistribute it and/or | |
| * modify it under the terms of the GNU Lesser General Public | |
| * License as published by the Free Software Foundation; either | |
| * version 2.1 of the License, or (at your option) any later version. | |
| * | |
| * FFmpeg is distributed in the hope that it will be useful, | |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| * Lesser General Public License for more details. | |
| * | |
| * You should have received a copy of the GNU Lesser General Public | |
| * License along with FFmpeg; if not, write to the Free Software | |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
| */ | |
| #include "libavutil/channel_layout.h" | |
| #include "libavutil/internal.h" | |
| #include "libavutil/intreadwrite.h" | |
| #include "libavcodec/mjpeg.h" | |
| #include "avformat.h" | |
| #include "demux.h" | |
| #include "internal.h" | |
| #include "avio.h" | |
| #define DEFAULT_PACKET_SIZE 1024 | |
| #define OVERREAD_SIZE 3 | |
| typedef struct MXGContext { | |
| uint8_t *buffer; | |
| uint8_t *buffer_ptr; | |
| uint8_t *soi_ptr; | |
| unsigned int buffer_size; | |
| int64_t dts; | |
| unsigned int cache_size; | |
| } MXGContext; | |
| static int mxg_read_header(AVFormatContext *s) | |
| { | |
| AVStream *video_st, *audio_st; | |
| MXGContext *mxg = s->priv_data; | |
| /* video parameters will be extracted from the compressed bitstream */ | |
| video_st = avformat_new_stream(s, NULL); | |
| if (!video_st) | |
| return AVERROR(ENOMEM); | |
| video_st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO; | |
| video_st->codecpar->codec_id = AV_CODEC_ID_MXPEG; | |
| avpriv_set_pts_info(video_st, 64, 1, 1000000); | |
| audio_st = avformat_new_stream(s, NULL); | |
| if (!audio_st) | |
| return AVERROR(ENOMEM); | |
| audio_st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO; | |
| audio_st->codecpar->codec_id = AV_CODEC_ID_PCM_ALAW; | |
| audio_st->codecpar->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO; | |
| audio_st->codecpar->sample_rate = 8000; | |
| audio_st->codecpar->bits_per_coded_sample = 8; | |
| audio_st->codecpar->block_align = 1; | |
| avpriv_set_pts_info(audio_st, 64, 1, 1000000); | |
| mxg->soi_ptr = mxg->buffer_ptr = mxg->buffer = 0; | |
| mxg->buffer_size = 0; | |
| mxg->dts = AV_NOPTS_VALUE; | |
| mxg->cache_size = 0; | |
| return 0; | |
| } | |
| static uint8_t* mxg_find_startmarker(uint8_t *p, uint8_t *end) | |
| { | |
| for (; p < end - 3; p += 4) { | |
| uint32_t x = AV_RN32(p); | |
| if (x & (~(x+0x01010101)) & 0x80808080) { | |
| if (p[0] == 0xff) { | |
| return p; | |
| } else if (p[1] == 0xff) { | |
| return p+1; | |
| } else if (p[2] == 0xff) { | |
| return p+2; | |
| } else if (p[3] == 0xff) { | |
| return p+3; | |
| } | |
| } | |
| } | |
| for (; p < end; ++p) { | |
| if (*p == 0xff) return p; | |
| } | |
| return end; | |
| } | |
| static int mxg_update_cache(AVFormatContext *s, unsigned int cache_size) | |
| { | |
| MXGContext *mxg = s->priv_data; | |
| unsigned int current_pos = mxg->buffer_ptr - mxg->buffer; | |
| unsigned int soi_pos; | |
| uint8_t *buffer; | |
| int ret; | |
| /* reallocate internal buffer */ | |
| if (current_pos > current_pos + cache_size) | |
| return AVERROR(ENOMEM); | |
| soi_pos = mxg->soi_ptr - mxg->buffer; | |
| buffer = av_fast_realloc(mxg->buffer, &mxg->buffer_size, | |
| current_pos + cache_size + | |
| AV_INPUT_BUFFER_PADDING_SIZE); | |
| if (!buffer) | |
| return AVERROR(ENOMEM); | |
| mxg->buffer = buffer; | |
| mxg->buffer_ptr = mxg->buffer + current_pos; | |
| if (mxg->soi_ptr) mxg->soi_ptr = mxg->buffer + soi_pos; | |
| /* get data */ | |
| ret = avio_read(s->pb, mxg->buffer_ptr + mxg->cache_size, | |
| cache_size - mxg->cache_size); | |
| if (ret < 0) | |
| return ret; | |
| mxg->cache_size += ret; | |
| memset(mxg->buffer_ptr + mxg->cache_size, 0, AV_INPUT_BUFFER_PADDING_SIZE); | |
| return ret; | |
| } | |
| static int mxg_read_packet(AVFormatContext *s, AVPacket *pkt) | |
| { | |
| int ret; | |
| unsigned int size; | |
| uint8_t *startmarker_ptr, *end, *search_end, marker; | |
| MXGContext *mxg = s->priv_data; | |
| while (!avio_feof(s->pb) && !s->pb->error){ | |
| if (mxg->cache_size <= OVERREAD_SIZE) { | |
| /* update internal buffer */ | |
| ret = mxg_update_cache(s, DEFAULT_PACKET_SIZE + OVERREAD_SIZE); | |
| if (ret < 0) | |
| return ret; | |
| } | |
| end = mxg->buffer_ptr + mxg->cache_size; | |
| /* find start marker - 0xff */ | |
| if (mxg->cache_size > OVERREAD_SIZE) { | |
| search_end = end - OVERREAD_SIZE; | |
| startmarker_ptr = mxg_find_startmarker(mxg->buffer_ptr, search_end); | |
| } else { | |
| search_end = end; | |
| startmarker_ptr = mxg_find_startmarker(mxg->buffer_ptr, search_end); | |
| if (startmarker_ptr >= search_end - 1 || | |
| *(startmarker_ptr + 1) != EOI) break; | |
| } | |
| if (startmarker_ptr != search_end) { /* start marker found */ | |
| marker = *(startmarker_ptr + 1); | |
| mxg->buffer_ptr = startmarker_ptr + 2; | |
| mxg->cache_size = end - mxg->buffer_ptr; | |
| if (marker == SOI) { | |
| mxg->soi_ptr = startmarker_ptr; | |
| } else if (marker == EOI) { | |
| if (!mxg->soi_ptr) { | |
| av_log(s, AV_LOG_WARNING, "Found EOI before SOI, skipping\n"); | |
| continue; | |
| } | |
| size = mxg->buffer_ptr - mxg->soi_ptr; | |
| ret = av_new_packet(pkt, size); | |
| if (ret < 0) | |
| return ret; | |
| memcpy(pkt->data, mxg->soi_ptr, size); | |
| pkt->pts = pkt->dts = mxg->dts; | |
| pkt->stream_index = 0; | |
| if (mxg->soi_ptr - mxg->buffer > mxg->cache_size) { | |
| if (mxg->cache_size > 0) { | |
| memmove(mxg->buffer, mxg->buffer_ptr, mxg->cache_size); | |
| } | |
| mxg->buffer_ptr = mxg->buffer; | |
| } | |
| mxg->soi_ptr = 0; | |
| return pkt->size; | |
| } else if ( (SOF0 <= marker && marker <= SOF15) || | |
| (SOS <= marker && marker <= COM) ) { | |
| /* all other markers that start marker segment also contain | |
| length value (see specification for JPEG Annex B.1) */ | |
| size = AV_RB16(mxg->buffer_ptr); | |
| if (size < 2) | |
| return AVERROR(EINVAL); | |
| if (mxg->cache_size < size) { | |
| ret = mxg_update_cache(s, size); | |
| if (ret < 0) | |
| return ret; | |
| startmarker_ptr = mxg->buffer_ptr - 2; | |
| mxg->cache_size = 0; | |
| } else { | |
| mxg->cache_size -= size; | |
| } | |
| mxg->buffer_ptr += size; | |
| if (marker == APP13 && size >= 16) { /* audio data */ | |
| ret = av_new_packet(pkt, size - 14); | |
| if (ret < 0) | |
| return ret; | |
| memcpy(pkt->data, startmarker_ptr + 16, size - 14); | |
| /* time (GMT) of first sample in usec since 1970, little-endian */ | |
| pkt->pts = pkt->dts = AV_RL64(startmarker_ptr + 8); | |
| pkt->stream_index = 1; | |
| if (startmarker_ptr - mxg->buffer > mxg->cache_size) { | |
| if (mxg->cache_size > 0) { | |
| memcpy(mxg->buffer, mxg->buffer_ptr, mxg->cache_size); | |
| } | |
| mxg->buffer_ptr = mxg->buffer; | |
| } | |
| return pkt->size; | |
| } else if (marker == COM && size >= 18 && | |
| !strncmp(startmarker_ptr + 4, "MXF", 3)) { | |
| /* time (GMT) of video frame in usec since 1970, little-endian */ | |
| mxg->dts = AV_RL64(startmarker_ptr + 12); | |
| } | |
| } | |
| } else { | |
| /* start marker not found */ | |
| mxg->buffer_ptr = search_end; | |
| mxg->cache_size = OVERREAD_SIZE; | |
| } | |
| } | |
| return AVERROR_EOF; | |
| } | |
| static int mxg_close(struct AVFormatContext *s) | |
| { | |
| MXGContext *mxg = s->priv_data; | |
| av_freep(&mxg->buffer); | |
| return 0; | |
| } | |
| const FFInputFormat ff_mxg_demuxer = { | |
| .p.name = "mxg", | |
| .p.long_name = NULL_IF_CONFIG_SMALL("MxPEG clip"), | |
| .p.extensions = "mxg", | |
| .priv_data_size = sizeof(MXGContext), | |
| .read_header = mxg_read_header, | |
| .read_packet = mxg_read_packet, | |
| .read_close = mxg_close, | |
| }; |