/* * 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 <inttypes.h> #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%"PRIx32"\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%"PRIx32"\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%"PRIx32"\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%"PRIx32"\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%"PRIx32"\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%"PRIx32"\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%"PRIx32"\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, 0, 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", .long_name = NULL_IF_CONFIG_SMALL("Apple MJPEG-B"), .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, };