[FFmpeg-devel] [PATCH] lavc/flacdec: Add frame CRC calculation

[James Almer]

On 20/02/13 12:05 PM, Paul B Mahol wrote:
> On 2/17/13, James Almer <jamrial at gmail.com> wrote:
>> On 17/02/13 11:00 AM, Michael Niedermayer wrote:
>>> On Sun, Feb 17, 2013 at 12:09:29AM -0300, James Almer wrote:
>>>>
>>>> Afaik, dropping the frame or not on crc checks currently depends on the
>>>> decoder and not the user.
>>>
>>> the user can change the options
>>>
>>> i think the check should be
>>> if(err & (AV_EF_CRCCHECK|AV_EF_COMPLIANT))
>>>
>>> and we should think about loosing AV_EF_CRCCHECK from the default
>>> flags
>>
>> What i meant is that currently, based on the value of err, most (or all)
>> decoders with frame crc checking either check for data integrity and drop
>> the frame if it's damaged, or don't check anything.
>> The user can choose to enable or disable the check, but the frame being
>> dropped or not if it's damaged is decided by the decoder (Returning < 0 or
>> not).
>>
>> I'm not sure what's best as default, but i think we should add a flag or
>> option to let the user choose to do a crc check without dropping the
>> frame (Only showing a warning) aside from the current "check, warn and drop"
>>
>> behavior every decoder is using.
> 
> You chech crc if AV_EF_CRCCHECK is set.
> 
> You drop one if AV_EF_COMPLIANT (or some better flag) is also set.

Fine by me. Not sure what others think, though (Of both this solution and the
flag).

Regards.