[FFmpeg-devel] [PATCH]lavf/cafdec: Do not fail hard for files ending with junk

[Paul B Mahol]

On 1/22/19, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
> 2019-01-22 11:56 GMT+01:00, Paul B Mahol <onemda at gmail.com>:
>> On 1/22/19, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
>>> 2019-01-22 11:38 GMT+01:00, Paul B Mahol <onemda at gmail.com>:
>>>> On 1/22/19, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
>>>>> 2019-01-22 11:28 GMT+01:00, Paul B Mahol <onemda at gmail.com>:
>>>>>> On 1/22/19, Paul B Mahol <onemda at gmail.com> wrote:
>>>>>>> On 1/22/19, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
>>>>>>>> 2019-01-15 13:17 GMT+01:00, Paul B Mahol <onemda at gmail.com>:
>>>>>>>>> On 1/15/19, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
>>>>>>>>>> 2019-01-15 12:53 GMT+01:00, Paul B Mahol <onemda at gmail.com>:
>>>>>>>>>>> On 1/15/19, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
>>>>>>>>>>>> 2019-01-15 10:23 GMT+01:00, Paul B Mahol <onemda at gmail.com>:
>>>>>>>>>>>>> On 1/15/19, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
>>>>>>>>>>>>
>>>>>>>>>>>>>> A user provided a real-life caf file ending with junk after
>>>>>>>>>>>>>> the
>>>>>>>>>>>>>> data
>>>>>>>>>>>>>> chunk, QuickTime reads such files.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Please comment, Carl Eugen
>>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> NACK, there is data after junk bytes, which would get simply
>>>>>>>>>>>>> discarded with your patch.
>>>>>>>>>>>>
>>>>>>>>>>>> Please elaborate: I don't think any data gets discarded because
>>>>>>>>>>>> of this patch.
>>>>>>>>>>>
>>>>>>>>>>> I told you already, hex edit size of data chunk to very big
>>>>>>>>>>> number
>>>>>>>>>>> and
>>>>>>>>>>> play file again.
>>>>>>>>>>
>>>>>>>>>> Of course.
>>>>>>>>>>
>>>>>>>>>> But how does this change the output compared to my patch?
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> It does change, full length of audio is:
>>>>>>>>>
>>>>>>>>> MD5=5128bc2cd0e7b0560f15dd4c0546d1a0rate=   0.0kbits/s speed= 777x
>>>>>>>>> size=       0kB time=00:09:18.16 bitrate=   0.0kbits/s speed= 769x
>>>>>>>>
>>>>>>>> Sorry for the delay:
>>>>>>>> QuickTime Player only plays the file for ~6:20.
>>>>>>>> Playing the file longer would be an issue since atoms after the
>>>>>>>> data atom are allowed.
>>>>>>>> And most important: This is unrelated, my patch is about playing
>>>>>>>> a file that is supposed to be played but currently doesn't work.
>>>>>>>> If there is something else to be improved, it should be a separate
>>>>>>>> patch.
>>>>>>>>
>>>>>>>> Please comment, Carl Eugen
>>>>>>>
>>>>>>> You can not claim it fixes playback.
>>>>>
>>>>> It does here: The file does not play without my patch, it plays
>>>>> (for the right duration) with my patch.
>>>>
>>>> Duration is not right at all.
>>>
>>> Does QuickTime play the file longer for you than FFmpeg
>>> with my patch?
>>> Or do I misunderstand you?
>>
>> Correct duration is one I showed it here.
>
> No, the correct duration for the given file is ~6:20 as
> already explained.

Nope, you are removing actual valid audio samples this way.