On Tue, 30 Jan 2018 13:43:25 +0100 wm4 <nfx...@googlemail.com> wrote:
> The ID3v2 "unsynchronization scheme" requires replacing any 0xFF 0x00 > sequences with 0xFF. This has to be done on every byte of the source > data, while the current code skipped a byte after a replacement. This > meant 0xFF 0x00 0xFF 00 was translated to 0xFF 0xFF 0x00 instead of 0xFF > 0xFF. It feels a bit messy to do this correctly with the avio use. But > fortunately, this translation can be done in-place, so we can just do it > in memory. > > Inspired by what taglib does. > --- > Sample (which had corrupted cover art, displays fine with the fix): > https://0x0.st/sbQ9.bin (unfortunately a bit too large for FATE) > --- > libavformat/id3v2.c | 26 ++++++++++++++------------ > 1 file changed, 14 insertions(+), 12 deletions(-) > > diff --git a/libavformat/id3v2.c b/libavformat/id3v2.c > index b80178d67a..f7de26a1d8 100644 > --- a/libavformat/id3v2.c > +++ b/libavformat/id3v2.c > @@ -976,19 +976,21 @@ static void id3v2_parse(AVIOContext *pb, AVDictionary > **metadata, > } > } > if (unsync || tunsync) { > - int64_t end = avio_tell(pb) + tlen; > - uint8_t *b; > - > - b = buffer; > - while (avio_tell(pb) < end && b - buffer < tlen && > !pb->eof_reached) { > - *b++ = avio_r8(pb); > - if (*(b - 1) == 0xff && avio_tell(pb) < end - 1 && > - b - buffer < tlen && > - !pb->eof_reached ) { > - uint8_t val = avio_r8(pb); > - *b++ = val ? val : avio_r8(pb); > - } > + uint8_t *b = buffer; > + uint8_t *t = buffer; > + uint8_t *end = t + tlen; > + > + if (avio_read(pb, buffer, tlen) != tlen) { > + av_log(s, AV_LOG_ERROR, "Failed to read tag data\n"); > + goto seek; > } > + > + while (t != end) { > + *b++ = *t++; > + if (t != end && t[-1] == 0xff && !t[0]) > + t++; > + } > + > ffio_init_context(&pb_local, buffer, b - buffer, 0, NULL, > NULL, NULL, > NULL); > tlen = b - buffer; Pushed, with a note about the old Libav commit added. _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
