diff options
Diffstat (limited to 'ffmpeg/libavcodec/mjpegbdec.c')
| -rw-r--r-- | ffmpeg/libavcodec/mjpegbdec.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/ffmpeg/libavcodec/mjpegbdec.c b/ffmpeg/libavcodec/mjpegbdec.c new file mode 100644 index 0000000..4327c10 --- /dev/null +++ b/ffmpeg/libavcodec/mjpegbdec.c @@ -0,0 +1,167 @@ +/* + * Apple MJPEG-B decoder + * Copyright (c) 2002 Alex Beregszaszi + * + * 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 + */ + +/** + * @file + * Apple MJPEG-B decoder. + */ + +#include "avcodec.h" +#include "mjpeg.h" +#include "mjpegdec.h" + +static uint32_t read_offs(AVCodecContext *avctx, GetBitContext *gb, uint32_t size, const char *err_msg){ + uint32_t offs= get_bits_long(gb, 32); + if(offs >= size){ + av_log(avctx, AV_LOG_WARNING, err_msg, offs, size); + return 0; + } + return offs; +} + +static int mjpegb_decode_frame(AVCodecContext *avctx, + void *data, int *got_frame, + AVPacket *avpkt) +{ + const uint8_t *buf = avpkt->data; + int buf_size = avpkt->size; + MJpegDecodeContext *s = avctx->priv_data; + const uint8_t *buf_end, *buf_ptr; + GetBitContext hgb; /* for the header */ + uint32_t dqt_offs, dht_offs, sof_offs, sos_offs, second_field_offs; + uint32_t field_size, sod_offs; + int ret; + + buf_ptr = buf; + buf_end = buf + buf_size; + s->got_picture = 0; + +read_header: + /* reset on every SOI */ + s->restart_interval = 0; + s->restart_count = 0; + s->mjpb_skiptosod = 0; + + if (buf_end - buf_ptr >= 1 << 28) + return AVERROR_INVALIDDATA; + + init_get_bits(&hgb, buf_ptr, /*buf_size*/(buf_end - buf_ptr)*8); + + skip_bits(&hgb, 32); /* reserved zeros */ + + if (get_bits_long(&hgb, 32) != MKBETAG('m','j','p','g')) + { + av_log(avctx, AV_LOG_WARNING, "not mjpeg-b (bad fourcc)\n"); + return AVERROR_INVALIDDATA; + } + + field_size = get_bits_long(&hgb, 32); /* field size */ + av_log(avctx, AV_LOG_DEBUG, "field size: 0x%x\n", field_size); + skip_bits(&hgb, 32); /* padded field size */ + second_field_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "second_field_offs is %d and size is %d\n"); + av_log(avctx, AV_LOG_DEBUG, "second field offs: 0x%x\n", second_field_offs); + + dqt_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "dqt is %d and size is %d\n"); + av_log(avctx, AV_LOG_DEBUG, "dqt offs: 0x%x\n", dqt_offs); + if (dqt_offs) + { + init_get_bits(&s->gb, buf_ptr+dqt_offs, (buf_end - (buf_ptr+dqt_offs))*8); + s->start_code = DQT; + if (ff_mjpeg_decode_dqt(s) < 0 && + (avctx->err_recognition & AV_EF_EXPLODE)) + return AVERROR_INVALIDDATA; + } + + dht_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "dht is %d and size is %d\n"); + av_log(avctx, AV_LOG_DEBUG, "dht offs: 0x%x\n", dht_offs); + if (dht_offs) + { + init_get_bits(&s->gb, buf_ptr+dht_offs, (buf_end - (buf_ptr+dht_offs))*8); + s->start_code = DHT; + ff_mjpeg_decode_dht(s); + } + + sof_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sof is %d and size is %d\n"); + av_log(avctx, AV_LOG_DEBUG, "sof offs: 0x%x\n", sof_offs); + if (sof_offs) + { + init_get_bits(&s->gb, buf_ptr+sof_offs, (buf_end - (buf_ptr+sof_offs))*8); + s->start_code = SOF0; + if (ff_mjpeg_decode_sof(s) < 0) + return -1; + } + + sos_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sos is %d and size is %d\n"); + av_log(avctx, AV_LOG_DEBUG, "sos offs: 0x%x\n", sos_offs); + sod_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sof is %d and size is %d\n"); + av_log(avctx, AV_LOG_DEBUG, "sod offs: 0x%x\n", sod_offs); + if (sos_offs) + { + init_get_bits(&s->gb, buf_ptr + sos_offs, + 8 * FFMIN(field_size, buf_end - buf_ptr - sos_offs)); + s->mjpb_skiptosod = (sod_offs - sos_offs - show_bits(&s->gb, 16)); + s->start_code = SOS; + if (ff_mjpeg_decode_sos(s, NULL, NULL) < 0 && + (avctx->err_recognition & AV_EF_EXPLODE)) + return AVERROR_INVALIDDATA; + } + + if (s->interlaced) { + s->bottom_field ^= 1; + /* if not bottom field, do not output image yet */ + if (s->bottom_field != s->interlace_polarity && second_field_offs) + { + buf_ptr = buf + second_field_offs; + goto read_header; + } + } + + //XXX FIXME factorize, this looks very similar to the EOI code + + if(!s->got_picture) { + av_log(avctx, AV_LOG_WARNING, "no picture\n"); + return buf_size; + } + + if ((ret = av_frame_ref(data, s->picture_ptr)) < 0) + return ret; + *got_frame = 1; + + if (!s->lossless && avctx->debug & FF_DEBUG_QP) { + av_log(avctx, AV_LOG_DEBUG, "QP: %d\n", + FFMAX3(s->qscale[0], s->qscale[1], s->qscale[2])); + } + + return buf_size; +} + +AVCodec ff_mjpegb_decoder = { + .name = "mjpegb", + .type = AVMEDIA_TYPE_VIDEO, + .id = AV_CODEC_ID_MJPEGB, + .priv_data_size = sizeof(MJpegDecodeContext), + .init = ff_mjpeg_decode_init, + .close = ff_mjpeg_decode_end, + .decode = mjpegb_decode_frame, + .capabilities = CODEC_CAP_DR1, + .max_lowres = 3, + .long_name = NULL_IF_CONFIG_SMALL("Apple MJPEG-B"), +}; |