[FFmpeg-devel] [PATCH] avformat/riffenc: fix handling monowhite when pix_fmt is not set

Mats Peterson matsp888 at yahoo.com
Tue Feb 23 17:23:32 CET 2016


On 02/23/2016 05:23 PM, Michael Niedermayer wrote:
> On Tue, Feb 23, 2016 at 04:14:09PM +0100, Mats Peterson wrote:
>> On 02/23/2016 03:54 PM, Michael Niedermayer wrote:
>>> On Tue, Feb 23, 2016 at 01:41:54PM +0100, Mats Peterson wrote:
>>>> On 02/23/2016 01:11 PM, Michael Niedermayer wrote:
>>>>> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
>>>>
>>>> When is pix_fmt AV_PIX_FMT_NONE in this context? Sorry if I sound
>>>> uninitiated.
>>>
>>> the pix_fmt describes the decoder output and encoder input
>>> demuxers may set it but do not have to (especially if theres nothing
>>> in their headers that contains that information)
>>>
>>> AV_PIX_FMT_NONE is the default if it has not been set
>>>
>>> this is documented in the header defining the field (avcodec.h)
>>>
>>> [...]
>>>
>>>
>>>
>>> _______________________________________________
>>> ffmpeg-devel mailing list
>>> ffmpeg-devel at ffmpeg.org
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>>>
>>
>> That sounds overly paranoid. I haven't been able to produce a case
>> where pix_fmt is AV_PIX_FMT_NONE here.
>>
>> Please answer the following questions:
>>
>> 1. What about "enum AVPixelFormat pix_fmt = enc->pix_fmt"? What good
>> does it do? enc->pix_fmt is already a proper AVPixelFormat enum.
>
> The code uses a temporary variable so it does not overwrite the callers
> input settings.
>

Exactly. I don't know what I was thinking here. Sorry.


>
>>
>> 2. You say that demuxers might not set the pixel format. This is on
>> the muxing side though. Isn't the pixel format always set when
>> muxing?
>
> theres no guratee that its set for the muxer
> there could be demuxer -> muxer with no decoder as well but thats
> not the only case, it could just be that the application doesnt
> set it, its not written in the API that the application has to set it
>
>

Yes, thank you.

Mats



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