On Mon, Jul 27, 2015 at 2:44 PM, Luca Barbato <[email protected]> wrote:
> On 27/07/15 15:35, Vittorio Giovara wrote:
>> On Sat, Jul 25, 2015 at 4:59 PM, Luca Barbato <[email protected]> wrote:
>>> And restrict the string to ascii text.
>>>
>>> CC: [email protected]
>>> ---
>>>
>>>  libavcodec/h264_sei.c | 53 
>>> +++++++++++++++++++++++++++++++++++++++++----------
>>>  1 file changed, 43 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/libavcodec/h264_sei.c b/libavcodec/h264_sei.c
>>> index 1f3844b..7a5c9d6 100644
>>> --- a/libavcodec/h264_sei.c
>>> +++ b/libavcodec/h264_sei.c
>>> @@ -191,24 +191,57 @@ static int decode_registered_user_data(H264Context 
>>> *h, int size)
>>>      return 0;
>>>  }
>>>
>>> -static int decode_unregistered_user_data(H264Context *h, int size)
>>> +static const uint8_t x264_version_uuid[] = {
>>> +    0xdc, 0x45, 0xe9, 0xbd, 0xe6, 0xd9, 0x48, 0xb7,
>>> +    0x96, 0x2c, 0xd8, 0x20, 0xd9, 0x23, 0xee, 0xef
>>> +};
>>> +
>>> +static int decode_x264_version(H264Context *h, int size)
>>>  {
>>> -    uint8_t user_data[16 + 256];
>>>      int e, build, i;
>>> +    uint8_t x264_string[256];
>>>
>>> -    if (size < 16)
>>> -        return AVERROR_INVALIDDATA;
>>>
>>> -    for (i = 0; i < sizeof(user_data) - 1 && i < size; i++)
>>> -        user_data[i] = get_bits(&h->gb, 8);
>>> +    for (i = 0; i < size && i < sizeof(x264_string) - 1; i++)
>>> +        x264_string[i] = get_bits(&h->gb, 8) & 0x7f;
>>> +
>>> +    x264_string[i] = 0;
>>>
>>> -    user_data[i] = 0;
>>> -    e = sscanf(user_data + 16, "x264 - core %d", &build);
>>> +    e = sscanf(x264_string, "x264 - core %d", &build);
>>>      if (e == 1 && build > 0)
>>> -        h->x264_build = build;
>>> +         h->x264_build = build;
>>>
>>>      if (h->avctx->debug & FF_DEBUG_BUGS)
>>> -        av_log(h->avctx, AV_LOG_DEBUG, "user data:\"%s\"\n", user_data + 
>>> 16);
>>> +        av_log(h->avctx, AV_LOG_DEBUG, "x264 version string:\"%s\"\n", 
>>> x264_string + 16);
>>> +
>>> +    for (; i < size; i++)
>>> +        skip_bits(&h->gb, 8);
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static int decode_unregistered_user_data(H264Context *h, int size)
>>> +{
>>> +    int i;
>>> +    uint8_t uuid[16];
>>> +
>>> +    if (size < 16)
>>> +        return AVERROR_INVALIDDATA;
>>> +
>>> +    for (i = 0; i < 16; i++)
>>> +        uuid[i] = get_bits(&h->gb, 8);
>>> +
>>> +    av_log(h->avctx, AV_LOG_DEBUG, "uuid 0x%02x 0x%02x 0x%02x 0x%02x "
>>> +                                   "0x%02x 0x%02x 0x%02x 0x%02x "
>>> +                                   "0x%02x 0x%02x 0x%02x 0x%02x "
>>> +                                   "0x%02x 0x%02x 0x%02x 0x%02x\n",
>>> +                                   uuid[0], uuid[1], uuid[2], uuid[3],
>>> +                                   uuid[4], uuid[5], uuid[6], uuid[7],
>>> +                                   uuid[8], uuid[9], uuid[10], uuid[11],
>>> +                                   uuid[12], uuid[13], uuid[14], uuid[15]);
>>> +
>>> +    if (!memcmp(uuid, x264_version_uuid, 16))
>>> +        return decode_x264_version(h, size - 16);
>>>
>>>      for (; i < size; i++)
>>>          skip_bits(&h->gb, 8);
>>> --
>>
>> why is this needed?
>>
>
> Make the parsing a little more robust and prevent printing garbage.
>
> I'm not exactly fond of using & 127 though.

mind mentioning this in the log?

> Probably I should rework the patch not to use sscanf to begin with.
> (printing garbage is a real concern thought?)

as you prefer
-- 
Vittorio
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