From 9bc281beae6dbf5d5f03cae8865b377f3a61f4ff Mon Sep 17 00:00:00 2001 From: Carl Eugen Hoyos Date: Mon, 18 Jan 2016 00:36:44 +0100 Subject: [PATCH] lavf/icodec: Improve autodetection. Avoids misdetection of MPEG (B-)frames. Reviewed-by: Michael Bradshaw --- libavformat/icodec.c | 28 +++++++++++++++++++++++++--- 1 file changed, 25 insertions(+), 3 deletions(-) diff --git a/libavformat/icodec.c b/libavformat/icodec.c index 22e209903b..6ddb901b7e 100644 --- a/libavformat/icodec.c +++ b/libavformat/icodec.c @@ -27,6 +27,7 @@ #include "libavutil/intreadwrite.h" #include "libavcodec/bytestream.h" #include "libavcodec/bmp.h" +#include "libavcodec/png.h" #include "avformat.h" #include "internal.h" @@ -44,9 +45,30 @@ typedef struct { static int probe(AVProbeData *p) { - if (AV_RL16(p->buf) == 0 && AV_RL16(p->buf + 2) == 1 && AV_RL16(p->buf + 4)) - return AVPROBE_SCORE_MAX / 4; - return 0; + unsigned i, frames = AV_RL16(p->buf + 4); + + if (AV_RL16(p->buf) || AV_RL16(p->buf + 2) != 1 || !frames) + return 0; + for (i = 0; i < frames; i++) { + unsigned offset; + if (AV_RL16(p->buf + 10 + i * 16) & ~1) + return FFMIN(i, AVPROBE_SCORE_MAX / 4); + if (p->buf[13 + i * 16]) + return FFMIN(i, AVPROBE_SCORE_MAX / 4); + if (AV_RL32(p->buf + 14 + i * 16) < 40) + return FFMIN(i, AVPROBE_SCORE_MAX / 4); + offset = AV_RL32(p->buf + 18 + i * 16); + if (offset < 22) + return FFMIN(i, AVPROBE_SCORE_MAX / 4); + if (offset + 8 > p->buf_size) + return AVPROBE_SCORE_MAX / 4 + FFMIN(i, 1); + if (p->buf[offset] != 40 && AV_RB64(p->buf + offset) != PNGSIG) + return FFMIN(i, AVPROBE_SCORE_MAX / 4); + if (i * 16 + 6 > p->buf_size) + return AVPROBE_SCORE_MAX / 4 + FFMIN(i, 1); + } + + return AVPROBE_SCORE_MAX / 2 + 1; } static int read_header(AVFormatContext *s)