From ec8a69fab657f9cce624e8b0f4069d12696890bf Mon Sep 17 00:00:00 2001 From: Vittorio Giovara Date: Tue, 29 Mar 2016 20:30:48 +0200 Subject: screenpresso: Correctly handle keyframes The first byte contains compression level together with keyframe status. When a frame is not interpreted correctly, its data is summed to the reference, and would degrade over time, producing an incorrect result. Signed-off-by: Vittorio Giovara --- libavcodec/screenpresso.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/libavcodec/screenpresso.c b/libavcodec/screenpresso.c index 41d1755328..819bd600fb 100644 --- a/libavcodec/screenpresso.c +++ b/libavcodec/screenpresso.c @@ -115,10 +115,9 @@ static int screenpresso_decode_frame(AVCodecContext *avctx, void *data, return AVERROR_INVALIDDATA; } - /* Basic sanity check, but not really harmful */ - if (avpkt->data[0] != 0x73 && avpkt->data[0] != 0x72) - av_log(avctx, AV_LOG_WARNING, "Unknown header 0x%02X\n", avpkt->data[0]); - keyframe = (avpkt->data[0] == 0x73); + /* Compression level (4 bits) and keyframe information (1 bit) */ + av_log(avctx, AV_LOG_DEBUG, "Compression level %d\n", avpkt->data[0] >> 4); + keyframe = avpkt->data[0] & 1; /* Pixel size */ component_size = ((avpkt->data[1] >> 2) & 0x03) + 1; -- cgit v1.2.3