[FFmpeg-devel] [libav-devel] [PATCH 1/2] matroskadec: check audio sample rate

[Andreas Cadhalpun]

On 15.06.2015 21:42, Luca Barbato wrote:
> On 15/06/15 21:17, Andreas Cadhalpun wrote:
>> And default to 8000 if it is invalid.
>>
>> An invalid sample rate can trigger av_assert2 in av_rescale_rnd.
> 
> No, it cannot.

That depends.

>> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>
>> ---
>>  libavformat/matroskadec.c | 8 ++++++++
>>  1 file changed, 8 insertions(+)
>>
>> diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
>> index 3512f0f..81dd53f 100644
>> --- a/libavformat/matroskadec.c
>> +++ b/libavformat/matroskadec.c
>> @@ -1680,6 +1680,14 @@ static int matroska_parse_tracks(AVFormatContext *s)
>>          if (!track->codec_id)
>>              continue;
>>  
>> +        if (track->audio.samplerate < 0 || track->audio.samplerate > INT_MAX ||
>> +            isnan(track->audio.samplerate)) {
>> +            av_log(matroska->ctx, AV_LOG_WARNING,
>> +                   "Invalid sample rate %f, defaulting to 8000 instead.\n",
>> +                   track->audio.samplerate);
>> +            track->audio.samplerate = 8000;
>> +        }
> 
> How can you get an invalid value here to begin with?

It gets read during ebml_parse.

> Replacing an
> invalid value with a made-up value doesn't sound right.

Well, 8000 is the default for MATROSKA_ID_AUDIOSAMPLINGFREQ.

Best regards,
Andreas