static int mjpeg_decode_frame(AVCodecContext *avctx, void *data, int *data_size, UINT8 *buf, int buf_size) { MJpegDecodeContext *s = avctx->priv_data; UINT8 *buf_end, *buf_ptr; int i, start_code; AVPicture *picture = data; *data_size = 0; /* no supplementary picture */ if (buf_size == 0) return 0; buf_ptr = buf; buf_end = buf + buf_size; while (buf_ptr < buf_end) { /* find start next marker */ start_code = find_marker(&buf_ptr, buf_end); { /* EOF */ if (start_code < 0) { goto the_end; } else { dprintf("marker=%x avail_size_in_buf=%d\n", start_code, buf_end - buf_ptr); if ((buf_end - buf_ptr) > s->buffer_size) { av_free(s->buffer); s->buffer_size = buf_end-buf_ptr; s->buffer = av_malloc(s->buffer_size); dprintf("buffer too small, expanding to %d bytes\n", s->buffer_size); } /* unescape buffer of SOS */ if (start_code == SOS) { UINT8 *src = buf_ptr; UINT8 *dst = s->buffer; while (src<buf_end) { UINT8 x = *(src++); *(dst++) = x; if (x == 0xff) { while(*src == 0xff) src++; x = *(src++); if (x >= 0xd0 && x <= 0xd7) *(dst++) = x; else if (x) break; } } init_get_bits(&s->gb, s->buffer, dst - s->buffer); dprintf("escaping removed %d bytes\n", (buf_end - buf_ptr) - (dst - s->buffer)); } else init_get_bits(&s->gb, buf_ptr, buf_end - buf_ptr); s->start_code = start_code; /* process markers */ if (start_code >= 0xd0 && start_code <= 0xd7) { dprintf("restart marker: %d\n", start_code&0x0f); } else if (s->first_picture) { /* APP fields */ if (start_code >= 0xe0 && start_code <= 0xef) mjpeg_decode_app(s); /* Comment */ else if (start_code == COM) mjpeg_decode_com(s); } switch(start_code) { case SOI: s->restart_interval = 0; /* nothing to do on SOI */ break; case DQT: mjpeg_decode_dqt(s); break; case DHT: mjpeg_decode_dht(s); break; case SOF0: if (mjpeg_decode_sof0(s) < 0) return -1; break; case EOI: eoi_parser: { if (s->interlaced) { s->bottom_field ^= 1; /* if not bottom field, do not output image yet */ if (s->bottom_field) goto not_the_end; } for(i=0;i<3;i++) { picture->data[i] = s->current_picture[i]; picture->linesize[i] = (s->interlaced) ? s->linesize[i] >> 1 : s->linesize[i]; } *data_size = sizeof(AVPicture); avctx->height = s->height; if (s->interlaced) avctx->height *= 2; avctx->width = s->width; /* XXX: not complete test ! */ switch((s->h_count[0] << 4) | s->v_count[0]) { case 0x11: avctx->pix_fmt = PIX_FMT_YUV444P; break; case 0x21: avctx->pix_fmt = PIX_FMT_YUV422P; break; default: case 0x22: avctx->pix_fmt = PIX_FMT_YUV420P; break; } /* dummy quality */ /* XXX: infer it with matrix */ // avctx->quality = 3; goto the_end; } break; case SOS: mjpeg_decode_sos(s); /* buggy avid puts EOI every 10-20th frame */ /* if restart period is over process EOI */ if ((s->buggy_avid && !s->interlaced) || s->restart_interval) goto eoi_parser; break; case DRI: mjpeg_decode_dri(s); break; case SOF1: case SOF2: case SOF3: case SOF5: case SOF6: case SOF7: case SOF9: case SOF10: case SOF11: case SOF13: case SOF14: case SOF15: case JPG: printf("mjpeg: unsupported coding type (%x)\n", start_code); break; // default: // printf("mjpeg: unsupported marker (%x)\n", start_code); // break; } not_the_end: /* eof process start code */ buf_ptr += (get_bits_count(&s->gb)+7)/8; dprintf("marker parser used %d bytes (%d bits)\n", (get_bits_count(&s->gb)+7)/8, get_bits_count(&s->gb)); } } } the_end: dprintf("mjpeg decode frame unused %d bytes\n", buf_end - buf_ptr); // return buf_end - buf_ptr; return buf_ptr - buf; }