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| author | Zhao Zhili <zhilizhao@tencent.com> | 2022-09-25 12:28:40 +0800 |
|---|---|---|
| committer | Zhao Zhili <zhilizhao@tencent.com> | 2022-10-08 22:56:20 +0800 |
| commit | 0d17f5228f4d3854066ec1001f69c7d1714b0df9 (patch) | |
| tree | 500477be72447bc1074bdd32aa3627d4023e2b56 | |
| parent | 2205ccd216bac64c08f2c3c7246dd19da745ef8d (diff) | |
| download | ffmpeg-0d17f5228f4d3854066ec1001f69c7d1714b0df9.tar.gz | |
avformat/mp3dec: avoid seek back and forth
avio_seek() is called inside check(). Seeking to 'off' then seeking
to 'off + i' is unefficient, and it can loop 64 * 1024 times in the
worst case. When probe a malformed file over HTTP, it looks like
stucked forvever. ffio_ensure_seekback() doesn't solve the issue
when the stream is seekable but slow.
Signed-off-by: Zhao Zhili <zhilizhao@tencent.com>
| -rw-r--r-- | libavformat/mp3dec.c | 16 |
1 files changed, 7 insertions, 9 deletions
diff --git a/libavformat/mp3dec.c b/libavformat/mp3dec.c index 458d6dbd03..a9e494452d 100644 --- a/libavformat/mp3dec.c +++ b/libavformat/mp3dec.c @@ -408,18 +408,11 @@ static int mp3_read_header(AVFormatContext *s) ffio_ensure_seekback(s->pb, i + 1024 + 4); frame_size = check(s->pb, off + i, &header); if (frame_size > 0) { - ret = avio_seek(s->pb, off, SEEK_SET); - if (ret < 0) - return ret; ffio_ensure_seekback(s->pb, i + 1024 + frame_size + 4); ret = check(s->pb, off + i + frame_size, &header2); if (ret >= 0 && (header & MP3_MASK) == (header2 & MP3_MASK)) { - av_log(s, i > 0 ? AV_LOG_INFO : AV_LOG_VERBOSE, "Skipping %d bytes of junk at %"PRId64".\n", i, off); - ret = avio_seek(s->pb, off + i, SEEK_SET); - if (ret < 0) - return ret; break; } else if (ret == CHECK_SEEK_FAILED) { av_log(s, AV_LOG_ERROR, "Invalid frame size (%d): Could not seek to %"PRId64".\n", frame_size, off + i + frame_size); @@ -429,10 +422,15 @@ static int mp3_read_header(AVFormatContext *s) av_log(s, AV_LOG_ERROR, "Failed to read frame size: Could not seek to %"PRId64".\n", (int64_t) (i + 1024 + frame_size + 4)); return AVERROR(EINVAL); } + } + if (i == 64 * 1024) { ret = avio_seek(s->pb, off, SEEK_SET); - if (ret < 0) - return ret; + } else { + av_log(s, i > 0 ? AV_LOG_INFO : AV_LOG_VERBOSE, "Skipping %d bytes of junk at %"PRId64".\n", i, off); + ret = avio_seek(s->pb, off + i, SEEK_SET); } + if (ret < 0) + return ret; off = avio_tell(s->pb); // the seek index is relative to the end of the xing vbr headers |