diff options
Diffstat (limited to 'libavcodec/h263dec.c')
| -rw-r--r-- | libavcodec/h263dec.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/libavcodec/h263dec.c b/libavcodec/h263dec.c new file mode 100644 index 0000000000..2af76199ab --- /dev/null +++ b/libavcodec/h263dec.c @@ -0,0 +1,205 @@ +/* + * H263 decoder + * Copyright (c) 2001 Gerard Lantau. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include "dsputil.h" +#include "avcodec.h" +#include "mpegvideo.h" + +//#define DEBUG + +static int h263_decode_init(AVCodecContext *avctx) +{ + MpegEncContext *s = avctx->priv_data; + + s->out_format = FMT_H263; + + s->width = avctx->width; + s->height = avctx->height; + + /* select sub codec */ + switch(avctx->codec->id) { + case CODEC_ID_H263: + break; + case CODEC_ID_OPENDIVX: + s->time_increment_bits = 4; /* default value for broken headers */ + s->h263_pred = 1; + break; + case CODEC_ID_MSMPEG4: + s->h263_msmpeg4 = 1; + s->h263_pred = 1; + break; + case CODEC_ID_H263I: + s->h263_intel = 1; + break; + default: + return -1; + } + + /* for h263, we allocate the images after having read the header */ + if (MPV_common_init(s) < 0) + return -1; + + if (s->h263_msmpeg4) + msmpeg4_decode_init_vlc(s); + else + h263_decode_init_vlc(s); + + return 0; +} + +static int h263_decode_end(AVCodecContext *avctx) +{ + MpegEncContext *s = avctx->priv_data; + + MPV_common_end(s); + return 0; +} + +static int h263_decode_frame(AVCodecContext *avctx, + void *data, int *data_size, + UINT8 *buf, int buf_size) +{ + MpegEncContext *s = avctx->priv_data; + int ret; + DCTELEM block[6][64]; + AVPicture *pict = data; + +#ifdef DEBUG + printf("*****frame %d size=%d\n", avctx->frame_number, buf_size); + printf("bytes=%x %x %x %x\n", buf[0], buf[1], buf[2], buf[3]); +#endif + + /* no supplementary picture */ + if (buf_size == 0) { + *data_size = 0; + return 0; + } + + init_get_bits(&s->gb, buf, buf_size); + + /* let's go :-) */ + if (s->h263_msmpeg4) { + ret = msmpeg4_decode_picture_header(s); + } else if (s->h263_pred) { + ret = mpeg4_decode_picture_header(s); + } else if (s->h263_intel) { + ret = intel_h263_decode_picture_header(s); + } else { + ret = h263_decode_picture_header(s); + } + if (ret < 0) + return -1; + + MPV_frame_start(s); + +#ifdef DEBUG + printf("qscale=%d\n", s->qscale); +#endif + + /* decode each macroblock */ + for(s->mb_y=0; s->mb_y < s->mb_height; s->mb_y++) { + for(s->mb_x=0; s->mb_x < s->mb_width; s->mb_x++) { +#ifdef DEBUG + printf("**mb x=%d y=%d\n", s->mb_x, s->mb_y); +#endif + /* DCT & quantize */ + if (s->h263_msmpeg4) { + msmpeg4_dc_scale(s); + } else if (s->h263_pred) { + h263_dc_scale(s); + } else { + /* default quantization values */ + s->y_dc_scale = 8; + s->c_dc_scale = 8; + } + + memset(block, 0, sizeof(block)); + s->mv_dir = MV_DIR_FORWARD; + s->mv_type = MV_TYPE_16X16; + if (s->h263_msmpeg4) { + if (msmpeg4_decode_mb(s, block) < 0) + return -1; + } else { + if (h263_decode_mb(s, block) < 0) + return -1; + } + MPV_decode_mb(s, block); + } + } + + MPV_frame_end(s); + + pict->data[0] = s->current_picture[0]; + pict->data[1] = s->current_picture[1]; + pict->data[2] = s->current_picture[2]; + pict->linesize[0] = s->linesize; + pict->linesize[1] = s->linesize / 2; + pict->linesize[2] = s->linesize / 2; + + avctx->quality = s->qscale; + *data_size = sizeof(AVPicture); + return buf_size; +} + +AVCodec opendivx_decoder = { + "opendivx", + CODEC_TYPE_VIDEO, + CODEC_ID_OPENDIVX, + sizeof(MpegEncContext), + h263_decode_init, + NULL, + h263_decode_end, + h263_decode_frame, +}; + +AVCodec h263_decoder = { + "h263", + CODEC_TYPE_VIDEO, + CODEC_ID_H263, + sizeof(MpegEncContext), + h263_decode_init, + NULL, + h263_decode_end, + h263_decode_frame, +}; + +AVCodec msmpeg4_decoder = { + "msmpeg4", + CODEC_TYPE_VIDEO, + CODEC_ID_MSMPEG4, + sizeof(MpegEncContext), + h263_decode_init, + NULL, + h263_decode_end, + h263_decode_frame, +}; + +AVCodec h263i_decoder = { + "h263i", + CODEC_TYPE_VIDEO, + CODEC_ID_H263I, + sizeof(MpegEncContext), + h263_decode_init, + NULL, + h263_decode_end, + h263_decode_frame, +}; + |