/* * 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" #include "internal.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 *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 = ff_reget_buffer(avctx, frame)) < 0) 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) { av_frame_set_decode_error_flags(frame, FF_DECODE_ERROR_INVALID_BITSTREAM); av_log(avctx, AV_LOG_WARNING, "Frame ended enexpectedly!\n"); break; } if (src[linelength - 1] != EOL) { av_frame_set_decode_error_flags(frame, 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) { av_frame_set_decode_error_flags(frame, 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) { av_frame_set_decode_error_flags(frame, 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; if ((ret = av_frame_ref(data, cpia->frame)) < 0) return ret; return avpkt->size; } static av_cold int cpia_decode_init(AVCodecContext *avctx) { CpiaContext *s = avctx->priv_data; // 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; } s->frame = av_frame_alloc(); if (!s->frame) return AVERROR(ENOMEM); return 0; } static av_cold int cpia_decode_end(AVCodecContext *avctx) { CpiaContext *s = avctx->priv_data; av_frame_free(&s->frame); return 0; } AVCodec ff_cpia_decoder = { .name = "cpia", .long_name = NULL_IF_CONFIG_SMALL("CPiA video format"), .type = AVMEDIA_TYPE_VIDEO, .id = AV_CODEC_ID_CPIA, .priv_data_size = sizeof(CpiaContext), .init = cpia_decode_init, .close = cpia_decode_end, .decode = cpia_decode_frame, .capabilities = CODEC_CAP_DR1, };