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ffmpeg/libavformat/mxg.c
Andreas Rheinhardt 790f793844 avutil/common: Don't auto-include mem.h 
There are lots of files that don't need it: The number of object
files that actually need it went down from 2011 to 884 here.

Keep it for external users in order to not cause breakages.

Also improve the other headers a bit while just at it.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2024-03-31 00:08:43 +01:00

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/*
* 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 "libavutil/mem.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;
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,
};
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