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

[James Almer]

On 16/02/13 11:35 PM, Michael Niedermayer wrote:
> On Sun, Feb 17, 2013 at 03:30:54AM +0100, Michael Niedermayer wrote:
>> On Sat, Feb 16, 2013 at 10:43:28PM -0300, James Almer wrote:
>>> On 16/02/13 9:30 PM, Michael Niedermayer wrote:
>>>> On Sat, Feb 16, 2013 at 08:56:18PM -0300, James Almer wrote:
>>>>> On 16/02/13 8:45 PM, Michael Niedermayer wrote:
>>>>>> On Sat, Feb 16, 2013 at 06:07:49AM -0300, James Almer wrote:
>>>>>>> Fixes ticket #2266
>>>>>>>
>>>>>>> Signed-off-by: James Almer <jamrial at gmail.com>
>>>>>>
>>
>>>>>> does this improve or worsen the way damaged files sound ?
>>
>> ping
> 
> to clarify
> 1. damage a flac file
> 2. listen to it with and without the patch
> 3. describe the results of how it sounds
> 
> we want the output to sound best
> we want to inform the user of damaged non lossless data
> we want to make it possible for the user to enable / disable hard CRC
> checks that discard data

I wrote a reply, saying that it would depend on how damaged is the file.

Also, I'm not sure how to do considerable damage to a file while avoiding 
triggering the many other checks made on it (subframe padding check, qlevel 
check, etc).
Using an hex editor i managed to change some random bytes to trigger crc 
errors, but as i said in my other reply, the difference was practically 
inaudible without the patch (With it, the dropped frame/s were somewhat 
noticeable since the audio skips).

Afaik, dropping the frame or not on crc checks currently depends on the 
decoder and not the user.

Regards.