| /* |
| * 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 "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->channels = 1; |
| audio_st->codecpar->channel_layout = AV_CH_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; |
| |
| 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; |
| } |
| |
| AVInputFormat ff_mxg_demuxer = { |
| .name = "mxg", |
| .long_name = NULL_IF_CONFIG_SMALL("MxPEG clip"), |
| .priv_data_size = sizeof(MXGContext), |
| .read_header = mxg_read_header, |
| .read_packet = mxg_read_packet, |
| .read_close = mxg_close, |
| .extensions = "mxg", |
| }; |