From 6b7e51e2b4facead9c45fb94647c85b58e6fdf22 Mon Sep 17 00:00:00 2001 From: Paul B Mahol Date: Wed, 27 Sep 2023 21:48:49 +0200 Subject: [PATCH] avcodec/photocd: allow decoding vlc with errors Also rename option that no longer works. Also make tables finding more robust. Signed-off-by: Paul B Mahol --- libavcodec/photocd.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/libavcodec/photocd.c b/libavcodec/photocd.c index 07e8d460bd..a9e42bb86a 100644 --- a/libavcodec/photocd.c +++ b/libavcodec/photocd.c @@ -277,8 +277,6 @@ static av_noinline int decode_huff(AVCodecContext *avctx, AVFrame *frame, if (get_bits_left(&g) <= 0) return AVERROR_INVALIDDATA; m = get_vlc2(&g, s->vlc[idx].table, s->vlc[idx].bits, 2); - if (m < 0) - return AVERROR_INVALIDDATA; m = sign_extend(m, 8); data[x] = av_clip_uint8(data[x] + m); } @@ -389,6 +387,7 @@ static int photocd_decode_frame(AVCodecContext *avctx, AVFrame *p, return AVERROR_INVALIDDATA; if (s->resolution == 4) { + s->streampos = (AV_RB16(avpkt->data + 2048 + 1536 + 3) + 12) * 2048; interp_pixels(ptr, p->linesize[0], img_info[4].width, img_info[4].height); interp_lines (ptr, p->linesize[0], img_info[4].width, img_info[4].height); @@ -396,7 +395,7 @@ static int photocd_decode_frame(AVCodecContext *avctx, AVFrame *p, if ((ret = read_hufftable(avctx, &s->vlc[n])) < 0) return ret; } - s->streampos = (s->streampos + 2047) & ~0x3ff; + s->streampos = (AV_RB16(avpkt->data + 2048 + 1536 + 3) + 14) * 2048; if (decode_huff(avctx, p, 4, 4) < 0) return AVERROR_INVALIDDATA; } @@ -447,7 +446,7 @@ static av_cold int photocd_decode_close(AVCodecContext *avctx) #define VD AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_DECODING_PARAM static const AVOption options[] = { - { "lowres", "Lower the decoding resolution by a power of two", + { "reduction", "Lower the decoding resolution by a power of two", OFFSET(lowres), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 4, VD }, { NULL }, }; -- 2.42.0