On Mon, Aug 11, 2025 at 08:04:02PM +0800, Zhao Zhili wrote: > > > > On Aug 11, 2025, at 18:51, Michael Niedermayer <mich...@niedermayer.cc> > > wrote: > > > > On Mon, Aug 11, 2025 at 11:37:55AM +0300, quink wrote: > >> PR #20212 opened by quink > >> URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20212 > >> Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20212.patch > >> > >> A set of files begins with the following byte sequence. > >> > >> 00000000 4c 41 4d 45 33 2e 31 30 30 aa aa aa aa aa aa aa > >> |LAME3.100.......| > >> 00000010 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa > >> |................| > >> * > >> > >> It seems they are encoded with lame, but missing header bytes at the > >> beginning. > >> > >> Signed-off-by: Zhao Zhili <zhiliz...@tencent.com> > >> > >> > >> From e24f7b8d0fbc4295b3dfc9832d7b552086f45ff0 Mon Sep 17 00:00:00 2001 > >> From: Zhao Zhili <zhiliz...@tencent.com> > >> Date: Mon, 11 Aug 2025 15:23:36 +0800 > >> Subject: [PATCH] avformat/mp3dec: Workaround mp3 detection failure > >> > >> A set of files begins with the following byte sequence. > >> > >> 00000000 4c 41 4d 45 33 2e 31 30 30 aa aa aa aa aa aa aa > >> |LAME3.100.......| > >> 00000010 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa > >> |................| > >> * > >> > >> It seems they are encoded with lame, but missing header bytes at the > >> beginning. > >> > >> Signed-off-by: Zhao Zhili <zhiliz...@tencent.com> > >> --- > >> libavformat/mp3dec.c | 7 +++++-- > >> 1 file changed, 5 insertions(+), 2 deletions(-) > >> > >> diff --git a/libavformat/mp3dec.c b/libavformat/mp3dec.c > >> index 31eeb68ebb..fd692a9c76 100644 > >> --- a/libavformat/mp3dec.c > >> +++ b/libavformat/mp3dec.c > >> @@ -121,8 +121,11 @@ static int mp3_read_probe(const AVProbeData *p) > >> // issues with MPEG-files! > >> if (first_frames>=7) return AVPROBE_SCORE_EXTENSION + 1; > >> else if (max_frames>200 && p->buf_size < 2*max_framesizes)return > >> AVPROBE_SCORE_EXTENSION; > >> - else if (max_frames>=4 && p->buf_size < 2*max_framesizes) return > >> AVPROBE_SCORE_EXTENSION / 2; > >> - else if (ff_id3v2_match(buf0, ID3v2_DEFAULT_MAGIC) && > >> 2*ff_id3v2_tag_len(buf0) >= p->buf_size) > >> + else if (max_frames>=4 && p->buf_size < 2*max_framesizes) { > >> + if (!memcmp(p->buf, "LAME3.100", sizeof("LAME3.100") - 1)) > >> + return AVPROBE_SCORE_EXTENSION - 2; > >> + return AVPROBE_SCORE_EXTENSION / 2; > >> + } else if (ff_id3v2_match(buf0, ID3v2_DEFAULT_MAGIC) && > >> 2*ff_id3v2_tag_len(buf0) >= p->buf_size) > > > > why is this needed ? > > > > Naively i would expect that the probe code would detect a mp3 stream like > > this > > based on max_frames > > why does that fail ? > > as what is teh stream detected instead ? > > maybe whatever detects it, is wrong instead and can be improved by not > > missdetecting it > > probe just report invalid data: > > Probing mp3 score:25 size:2048 > Probing h263 score:25 size:4096 > Probing mp3 score:25 size:4096 > Probing h263 score:25 size:8192 > Probing mp3 score:25 size:8192 > Probing h263 score:25 size:16384 > Probing mp3 score:25 size:16384 > Probing h263 score:25 size:20160 > Probing mp3 score:25 size:20160 > Probing h263 score:25 size:20160 > Probing mp3 score:25 size:20160 > [AVIOContext @ 0x127f04ac0] Statistics: 20160 bytes read, 0 seeks > > 3ac558a6ebf467b42e4a42be3014c6c5.mp3: Invalid data found when processing input > > These files are only 1 to 2 seconds contains a single English word. I think > the size of file > is one of the reason of failed to detect.
they are valid h263 ? if not, can teh h263 probe test be improved so they are not detected as h263? thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB He who knows, does not speak. He who speaks, does not know. -- Lao Tsu
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