yading@10: /*
yading@10:  * CPiA video decoder.
yading@10:  * Copyright (c) 2010 Hans de Goede <hdegoede@redhat.com>
yading@10:  *
yading@10:  * This decoder is based on the LGPL code available at
yading@10:  * https://v4l4j.googlecode.com/svn/v4l4j/trunk/libvideo/libv4lconvert/cpia1.c
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: #include "avcodec.h"
yading@10: #include "get_bits.h"
yading@10: #include "internal.h"
yading@10: 
yading@10: 
yading@10: #define FRAME_HEADER_SIZE 64
yading@10: #define MAGIC_0         0x19    /**< First header byte */
yading@10: #define MAGIC_1         0x68    /**< Second header byte */
yading@10: #define SUBSAMPLE_420      0
yading@10: #define SUBSAMPLE_422      1
yading@10: #define YUVORDER_YUYV      0
yading@10: #define YUVORDER_UYVY      1
yading@10: #define NOT_COMPRESSED     0
yading@10: #define COMPRESSED         1
yading@10: #define NO_DECIMATION      0
yading@10: #define DECIMATION_ENAB    1
yading@10: #define EOL             0xfd    /**< End Of Line marker */
yading@10: #define EOI             0xff    /**< End Of Image marker */
yading@10: 
yading@10: 
yading@10: typedef struct {
yading@10:     AVFrame *frame;
yading@10: } CpiaContext;
yading@10: 
yading@10: 
yading@10: static int cpia_decode_frame(AVCodecContext *avctx,
yading@10:                              void *data, int *got_frame, AVPacket* avpkt)
yading@10: {
yading@10:     CpiaContext* const cpia = avctx->priv_data;
yading@10:     int i,j,ret;
yading@10: 
yading@10:     uint8_t* const header = avpkt->data;
yading@10:     uint8_t* src;
yading@10:     int src_size;
yading@10:     uint16_t linelength;
yading@10:     uint8_t skip;
yading@10: 
yading@10:     AVFrame *frame = cpia->frame;
yading@10:     uint8_t *y, *u, *v, *y_end, *u_end, *v_end;
yading@10: 
yading@10:     // Check header
yading@10:     if ( avpkt->size < FRAME_HEADER_SIZE
yading@10:       || header[0] != MAGIC_0 || header[1] != MAGIC_1
yading@10:       || (header[17] != SUBSAMPLE_420 && header[17] != SUBSAMPLE_422)
yading@10:       || (header[18] != YUVORDER_YUYV && header[18] != YUVORDER_UYVY)
yading@10:       || (header[28] != NOT_COMPRESSED && header[28] != COMPRESSED)
yading@10:       || (header[29] != NO_DECIMATION && header[29] != DECIMATION_ENAB)
yading@10:     ) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "Invalid header!\n");
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     // currently unsupported properties
yading@10:     if (header[17] == SUBSAMPLE_422) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "Unsupported subsample!\n");
yading@10:         return AVERROR_PATCHWELCOME;
yading@10:     }
yading@10:     if (header[18] == YUVORDER_UYVY) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "Unsupported YUV byte order!\n");
yading@10:         return AVERROR_PATCHWELCOME;
yading@10:     }
yading@10:     if (header[29] == DECIMATION_ENAB) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "Decimation unsupported!\n");
yading@10:         return AVERROR_PATCHWELCOME;
yading@10:     }
yading@10: 
yading@10:     src = header + FRAME_HEADER_SIZE;
yading@10:     src_size = avpkt->size - FRAME_HEADER_SIZE;
yading@10: 
yading@10:     if (header[28] == NOT_COMPRESSED) {
yading@10:         frame->pict_type = AV_PICTURE_TYPE_I;
yading@10:         frame->key_frame = 1;
yading@10:     } else {
yading@10:         frame->pict_type = AV_PICTURE_TYPE_P;
yading@10:         frame->key_frame = 0;
yading@10:     }
yading@10: 
yading@10:     // Get buffer filled with previous frame
yading@10:     if ((ret = ff_reget_buffer(avctx, frame)) < 0)
yading@10:         return ret;
yading@10: 
yading@10: 
yading@10:     for ( i = 0;
yading@10:           i < frame->height;
yading@10:           i++, src += linelength, src_size -= linelength
yading@10:     ) {
yading@10:         // Read line length, two byte little endian
yading@10:         linelength = AV_RL16(src);
yading@10:         src += 2;
yading@10: 
yading@10:         if (src_size < linelength) {
yading@10:             av_frame_set_decode_error_flags(frame, FF_DECODE_ERROR_INVALID_BITSTREAM);
yading@10:             av_log(avctx, AV_LOG_WARNING, "Frame ended enexpectedly!\n");
yading@10:             break;
yading@10:         }
yading@10:         if (src[linelength - 1] != EOL) {
yading@10:             av_frame_set_decode_error_flags(frame, FF_DECODE_ERROR_INVALID_BITSTREAM);
yading@10:             av_log(avctx, AV_LOG_WARNING, "Wrong line length %d or line not terminated properly (found 0x%02x)!\n", linelength, src[linelength - 1]);
yading@10:             break;
yading@10:         }
yading@10: 
yading@10:         /* Update the data pointers. Y data is on every line.
yading@10:          * U and V data on every second line
yading@10:          */
yading@10:         y = &frame->data[0][i * frame->linesize[0]];
yading@10:         u = &frame->data[1][(i >> 1) * frame->linesize[1]];
yading@10:         v = &frame->data[2][(i >> 1) * frame->linesize[2]];
yading@10:         y_end = y + frame->linesize[0] - 1;
yading@10:         u_end = u + frame->linesize[1] - 1;
yading@10:         v_end = v + frame->linesize[2] - 1;
yading@10: 
yading@10:         if ((i & 1) && header[17] == SUBSAMPLE_420) {
yading@10:             /* We are on a odd line and 420 subsample is used.
yading@10:              * On this line only Y values are specified, one per pixel.
yading@10:              */
yading@10:             for (j = 0; j < linelength - 1; j++) {
yading@10:                 if (y > y_end) {
yading@10:                     av_frame_set_decode_error_flags(frame, FF_DECODE_ERROR_INVALID_BITSTREAM);
yading@10:                     av_log(avctx, AV_LOG_WARNING, "Decoded data exceeded linesize!\n");
yading@10:                     break;
yading@10:                 }
yading@10:                 if ((src[j] & 1) && header[28] == COMPRESSED) {
yading@10:                     /* It seems that odd lines are always uncompressed, but
yading@10:                      * we do it according to specification anyways.
yading@10:                      */
yading@10:                     skip = src[j] >> 1;
yading@10:                     y += skip;
yading@10:                 } else {
yading@10:                     *(y++) = src[j];
yading@10:                 }
yading@10:             }
yading@10:         } else if (header[17] == SUBSAMPLE_420) {
yading@10:             /* We are on an even line and 420 subsample is used.
yading@10:              * On this line each pair of pixels is described by four bytes.
yading@10:              */
yading@10:             for (j = 0; j < linelength - 4; ) {
yading@10:                 if (y + 1 > y_end || u > u_end || v > v_end) {
yading@10:                     av_frame_set_decode_error_flags(frame, FF_DECODE_ERROR_INVALID_BITSTREAM);
yading@10:                     av_log(avctx, AV_LOG_WARNING, "Decoded data exceeded linesize!\n");
yading@10:                     break;
yading@10:                 }
yading@10:                 if ((src[j] & 1) && header[28] == COMPRESSED) {
yading@10:                     // Skip amount of pixels and move forward one byte
yading@10:                     skip = src[j] >> 1;
yading@10:                     y += skip;
yading@10:                     u += skip >> 1;
yading@10:                     v += skip >> 1;
yading@10:                     j++;
yading@10:                 } else {
yading@10:                     // Set image data as specified and move forward 4 bytes
yading@10:                     *(y++) = src[j];
yading@10:                     *(u++) = src[j+1];
yading@10:                     *(y++) = src[j+2];
yading@10:                     *(v++) = src[j+3];
yading@10:                     j += 4;
yading@10:                 }
yading@10:             }
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     *got_frame = 1;
yading@10:     if ((ret = av_frame_ref(data, cpia->frame)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     return avpkt->size;
yading@10: }
yading@10: 
yading@10: static av_cold int cpia_decode_init(AVCodecContext *avctx)
yading@10: {
yading@10:     CpiaContext *s = avctx->priv_data;
yading@10: 
yading@10:     // output pixel format
yading@10:     avctx->pix_fmt = AV_PIX_FMT_YUV420P;
yading@10: 
yading@10:     /* The default timebase set by the v4l2 demuxer leads to probing which is buggy.
yading@10:      * Set some reasonable time_base to skip this.
yading@10:      */
yading@10:     if (avctx->time_base.num == 1 && avctx->time_base.den == 1000000) {
yading@10:         avctx->time_base.num = 1;
yading@10:         avctx->time_base.den = 60;
yading@10:     }
yading@10: 
yading@10:     s->frame = av_frame_alloc();
yading@10:     if (!s->frame)
yading@10:         return AVERROR(ENOMEM);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static av_cold int cpia_decode_end(AVCodecContext *avctx)
yading@10: {
yading@10:     CpiaContext *s = avctx->priv_data;
yading@10: 
yading@10:     av_frame_free(&s->frame);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: AVCodec ff_cpia_decoder = {
yading@10:     .name           = "cpia",
yading@10:     .type           = AVMEDIA_TYPE_VIDEO,
yading@10:     .id             = AV_CODEC_ID_CPIA,
yading@10:     .priv_data_size = sizeof(CpiaContext),
yading@10:     .init           = cpia_decode_init,
yading@10:     .close          = cpia_decode_end,
yading@10:     .decode         = cpia_decode_frame,
yading@10:     .capabilities   = CODEC_CAP_DR1,
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("CPiA video format"),
yading@10: };