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/*
* CPiA video decoder.
* Copyright (c) 2010 Hans de Goede <hdegoede@redhat.com>
*
* This decoder is based on the LGPL code available at
* https://v4l4j.googlecode.com/svn/v4l4j/trunk/libvideo/libv4lconvert/cpia1.c
*
* 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 "avcodec.h"
#include "get_bits.h"
#define FRAME_HEADER_SIZE 64
#define MAGIC_0 0x19 /**< First header byte */
#define MAGIC_1 0x68 /**< Second header byte */
#define SUBSAMPLE_420 0
#define SUBSAMPLE_422 1
#define YUVORDER_YUYV 0
#define YUVORDER_UYVY 1
#define NOT_COMPRESSED 0
#define COMPRESSED 1
#define NO_DECIMATION 0
#define DECIMATION_ENAB 1
#define EOL 0xfd /**< End Of Line marker */
#define EOI 0xff /**< End Of Image marker */
typedef struct {
AVFrame frame;
} CpiaContext;
static int cpia_decode_frame(AVCodecContext* avctx,
void* data, int* data_size, AVPacket* avpkt)
{
CpiaContext* const cpia = avctx->priv_data;
int i,j,ret;
uint8_t* const header = avpkt->data;
uint8_t* src;
int src_size;
uint16_t linelength;
uint8_t skip;
AVFrame* const frame = &cpia->frame;
uint8_t *y, *u, *v, *y_end, *u_end, *v_end;
// Get buffer filled with previous frame
if ((ret = avctx->reget_buffer(avctx, frame)) < 0) {
av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed!\n");
return ret;
}
// Check header
if ( avpkt->size < FRAME_HEADER_SIZE
|| header[0] != MAGIC_0 || header[1] != MAGIC_1
|| (header[17] != SUBSAMPLE_420 && header[17] != SUBSAMPLE_422)
|| (header[18] != YUVORDER_YUYV && header[18] != YUVORDER_UYVY)
|| (header[28] != NOT_COMPRESSED && header[28] != COMPRESSED)
|| (header[29] != NO_DECIMATION && header[29] != DECIMATION_ENAB)
) {
av_log(avctx, AV_LOG_ERROR, "Invalid header!\n");
return AVERROR_INVALIDDATA;
}
// currently unsupported properties
if (header[17] == SUBSAMPLE_422) {
av_log(avctx, AV_LOG_ERROR, "Unsupported subsample!\n");
return AVERROR_PATCHWELCOME;
}
if (header[18] == YUVORDER_UYVY) {
av_log(avctx, AV_LOG_ERROR, "Unsupported YUV byte order!\n");
return AVERROR_PATCHWELCOME;
}
if (header[29] == DECIMATION_ENAB) {
av_log(avctx, AV_LOG_ERROR, "Decimation unsupported!\n");
return AVERROR_PATCHWELCOME;
}
src = header + FRAME_HEADER_SIZE;
src_size = avpkt->size - FRAME_HEADER_SIZE;
if (header[28] == NOT_COMPRESSED) {
frame->pict_type = AV_PICTURE_TYPE_I;
frame->key_frame = 1;
} else {
frame->pict_type = AV_PICTURE_TYPE_P;
frame->key_frame = 0;
}
for ( i = 0;
i < frame->height;
i++, src += linelength, src_size -= linelength
) {
// Read line length, two byte little endian
linelength = AV_RL16(src);
src += 2;
if (src_size < linelength) {
frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM;
av_log(avctx, AV_LOG_WARNING, "Frame ended enexpectedly!\n");
break;
}
if (src[linelength - 1] != EOL) {
frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM;
av_log(avctx, AV_LOG_WARNING, "Wrong line length %d or line not terminated properly (found 0x%02x)!\n", linelength, src[linelength - 1]);
break;
}
/* Update the data pointers. Y data is on every line.
* U and V data on every second line
*/
y = &frame->data[0][i * frame->linesize[0]];
u = &frame->data[1][(i >> 1) * frame->linesize[1]];
v = &frame->data[2][(i >> 1) * frame->linesize[2]];
y_end = y + frame->linesize[0] - 1;
u_end = u + frame->linesize[1] - 1;
v_end = v + frame->linesize[2] - 1;
if ((i & 1) && header[17] == SUBSAMPLE_420) {
/* We are on a odd line and 420 subsample is used.
* On this line only Y values are specified, one per pixel.
*/
for (j = 0; j < linelength - 1; j++) {
if (y > y_end) {
frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM;
av_log(avctx, AV_LOG_WARNING, "Decoded data exceeded linesize!\n");
break;
}
if ((src[j] & 1) && header[28] == COMPRESSED) {
/* It seems that odd lines are always uncompressed, but
* we do it according to specification anyways.
*/
skip = src[j] >> 1;
y += skip;
} else {
*(y++) = src[j];
}
}
} else if (header[17] == SUBSAMPLE_420) {
/* We are on an even line and 420 subsample is used.
* On this line each pair of pixels is described by four bytes.
*/
for (j = 0; j < linelength - 4; ) {
if (y + 1 > y_end || u > u_end || v > v_end) {
frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM;
av_log(avctx, AV_LOG_WARNING, "Decoded data exceeded linesize!\n");
break;
}
if ((src[j] & 1) && header[28] == COMPRESSED) {
// Skip amount of pixels and move forward one byte
skip = src[j] >> 1;
y += skip;
u += skip >> 1;
v += skip >> 1;
j++;
} else {
// Set image data as specified and move forward 4 bytes
*(y++) = src[j];
*(u++) = src[j+1];
*(y++) = src[j+2];
*(v++) = src[j+3];
j += 4;
}
}
}
}
*data_size = sizeof(AVFrame);
*(AVFrame*) data = *frame;
return avpkt->size;
}
static av_cold int cpia_decode_init(AVCodecContext *avctx)
{
// output pixel format
avctx->pix_fmt = PIX_FMT_YUV420P;
/* The default timebase set by the v4l2 demuxer leads to probing which is buggy.
* Set some reasonable time_base to skip this.
*/
if (avctx->time_base.num == 1 && avctx->time_base.den == 1000000) {
avctx->time_base.num = 1;
avctx->time_base.den = 60;
}
return 0;
}
AVCodec ff_cpia_decoder = {
.name = "cpia",
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_CPIA,
.priv_data_size = sizeof(CpiaContext),
.init = cpia_decode_init,
.decode = cpia_decode_frame,
.capabilities = CODEC_CAP_DR1,
.long_name = NULL_IF_CONFIG_SMALL("CPiA video format"),
};
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