251 lines
8.1 KiB
C
251 lines
8.1 KiB
C
/*
|
|
* MxPEG clip file demuxer
|
|
* Copyright (c) 2010 Anatoly Nenashev
|
|
*
|
|
* This file is part of Libav.
|
|
*
|
|
* Libav 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.
|
|
*
|
|
* Libav 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 Libav; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
#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->codec->codec_type = AVMEDIA_TYPE_VIDEO;
|
|
video_st->codec->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->codec->codec_type = AVMEDIA_TYPE_AUDIO;
|
|
audio_st->codec->codec_id = AV_CODEC_ID_PCM_ALAW;
|
|
audio_st->codec->channels = 1;
|
|
audio_st->codec->sample_rate = 8000;
|
|
audio_st->codec->bits_per_coded_sample = 8;
|
|
audio_st->codec->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 = *(uint32_t*)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;
|
|
int ret;
|
|
|
|
/* reallocate internal buffer */
|
|
if (current_pos > current_pos + cache_size)
|
|
return AVERROR(ENOMEM);
|
|
if (mxg->soi_ptr) soi_pos = mxg->soi_ptr - mxg->buffer;
|
|
mxg->buffer = av_fast_realloc(mxg->buffer, &mxg->buffer_size,
|
|
current_pos + cache_size +
|
|
FF_INPUT_BUFFER_PADDING_SIZE);
|
|
if (!mxg->buffer)
|
|
return AVERROR(ENOMEM);
|
|
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 (!s->pb->eof_reached && !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;
|
|
}
|
|
|
|
pkt->pts = pkt->dts = mxg->dts;
|
|
pkt->stream_index = 0;
|
|
pkt->destruct = NULL;
|
|
pkt->size = mxg->buffer_ptr - mxg->soi_ptr;
|
|
pkt->data = mxg->soi_ptr;
|
|
|
|
if (mxg->soi_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;
|
|
}
|
|
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 */
|
|
/* time (GMT) of first sample in usec since 1970, little-endian */
|
|
pkt->pts = pkt->dts = AV_RL64(startmarker_ptr + 8);
|
|
pkt->stream_index = 1;
|
|
pkt->destruct = NULL;
|
|
pkt->size = size - 14;
|
|
pkt->data = startmarker_ptr + 16;
|
|
|
|
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",
|
|
};
|