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Diffstat (limited to 'libavcodec/cpia.c')
| -rw-r--r-- | libavcodec/cpia.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/libavcodec/cpia.c b/libavcodec/cpia.c new file mode 100644 index 0000000..f741eb9 --- /dev/null +++ b/libavcodec/cpia.c @@ -0,0 +1,218 @@ +/* + * 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 *got_frame, 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; + + // 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; + } + + // 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; + } + + + 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; + } + } + } + } + + *got_frame = 1; + *(AVFrame*) data = *frame; + + return avpkt->size; +} + +static av_cold int cpia_decode_init(AVCodecContext *avctx) +{ + // output pixel format + avctx->pix_fmt = AV_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"), +}; |
