On Sat, Jun 03, 2017 at 06:14:12PM -0300, James Almer wrote:
> On 6/3/2017 5:16 PM, Michael Niedermayer wrote:
> > On Sat, Jun 03, 2017 at 12:33:33AM -0300, James Almer wrote:
> >> Atempt to read and propagate only full ADTS frames and not other data,
> >> like id3v1 or APETags at the end of the file.
> >>
> >> Fixes ticket #6439.
> >>
> >> Signed-off-by: James Almer <jamr...@gmail.com>
> >> ---
> >> libavformat/aacdec.c | 42 ++++++++++++++++++++++++++++++++++++++++--
> >> 1 file changed, 40 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/libavformat/aacdec.c b/libavformat/aacdec.c
> >> index 5ab5197e33..aee1efe03c 100644
> >> --- a/libavformat/aacdec.c
> >> +++ b/libavformat/aacdec.c
> >> @@ -23,10 +23,11 @@
> >> #include "libavutil/intreadwrite.h"
> >> #include "avformat.h"
> >> #include "internal.h"
> >> -#include "rawdec.h"
> >> #include "id3v1.h"
> >> #include "apetag.h"
> >>
> >> +#define ADTS_HEADER_SIZE 7
> >> +
> >> static int adts_aac_probe(AVProbeData *p)
> >> {
> >> int max_frames = 0, first_frames = 0;
> >> @@ -79,6 +80,7 @@ static int adts_aac_probe(AVProbeData *p)
> >> static int adts_aac_read_header(AVFormatContext *s)
> >> {
> >> AVStream *st;
> >> + uint16_t state;
> >>
> >> st = avformat_new_stream(s, NULL);
> >> if (!st)
> >> @@ -96,18 +98,54 @@ static int adts_aac_read_header(AVFormatContext *s)
> >> avio_seek(s->pb, cur, SEEK_SET);
> >> }
> >>
> >> + // skip data until the first ADTS frame is found
> >> + state = avio_r8(s->pb);
> >> + while (!avio_feof(s->pb)) {
> >> + state = (state << 8) | avio_r8(s->pb);
> >> + if ((state >> 4) != 0xFFF)
> >> + continue;
> >> + avio_seek(s->pb, -2, SEEK_CUR);
> >> + break;
> >> + }
> >
> > this would loop forever with /dev/zero as input
>
> How can i prevent this? Maybe checking a max of
> AVFormatContext.probesize or AVFormatContext.format_probesize bytes
> before bailing out? Which one if so?id tend toward probesize, but anything will do. thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB I know you won't believe me, but the highest form of Human Excellence is to question oneself and others. -- Socrates
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