[libav-devel] [PATCH] h264: Parse only the x264 info unregisterd sei

Luca Barbato lu_zero at gentoo.org
Sat Aug 1 20:44:57 CEST 2015


On 01/08/15 20:32, Anton Khirnov wrote:
> Quoting Luca Barbato (2015-08-01 14:16:45)
>> On 31/07/15 07:59, Anton Khirnov wrote:
>>> Quoting Luca Barbato (2015-07-29 22:51:05)
>>>> And restrict the string to ascii text.
>>>>
>>>> CC: libav-stable at libav.org
>>>>
>>>> Signed-off-by: Luca Barbato <lu_zero at gentoo.org>
>>>> ---
>>>>  libavcodec/h264_sei.c | 57 ++++++++++++++++++++++++++++++++++++++++++---------
>>>>  1 file changed, 47 insertions(+), 10 deletions(-)
>>>>
>>>> diff --git a/libavcodec/h264_sei.c b/libavcodec/h264_sei.c
>>>> index 1f3844b..7361941 100644
>>>> --- a/libavcodec/h264_sei.c
>>>> +++ b/libavcodec/h264_sei.c
>>>> @@ -191,24 +191,61 @@ static int decode_registered_user_data(H264Context *h, int size)
>>>>      return 0;
>>>>  }
>>>>  
>>>> +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)
>>>> +{
>>>> +    int build = 0, i = 0;
>>>> +    uint8_t x264_string[256];
>>>> +
>>>> +    if (size < 13)
>>>> +        goto skip;
>>>> +
>>>> +    for (i = 0; i < size && i < sizeof(x264_string) - 1; i++)
>>>> +        x264_string[i] = get_bits(&h->gb, 8) & 0x7f;
>>>
>>> I don't think this is enough, there are still control characters in this
>>> range (or the caller can have a weird character set). Either filter out
>>> everything before ' ', or use isprint() perhaps?
>>>
>>>> +
>>>> +    x264_string[i] = 0;
>>>> +
>>>> +    if (!memcmp(x264_string, "x264 - core ", 12))
>>>> +        build = atoi(x264_string + 12);
>>>> +
>>>> +    if (build > 0)
>>>> +         h->x264_build = build;
>>>> +
>>>> +    if (h->avctx->debug & FF_DEBUG_BUGS)
>>>> +        av_log(h->avctx, AV_LOG_DEBUG, "x264 version string:\"%s\"\n", x264_string);
>>>> +skip:
>>>> +    for (; i < size; i++)
>>>> +        skip_bits(&h->gb, 8);
>>>
>>> Why duplicate this?
>>>
>>
>> Duplicate what exactly?
> 
> This exact same loop is also at the end of
> decode_unregistered_user_data()
> 

I can rework to return the consumed size from both probably.





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