[FFmpeg-devel] doc/codecs: Add missing documentation for hwaccel_flags.

From e030510864c28d4b17c8d1eb09ab00f274bf5dcc Mon Sep 17 00:00:00 2001
From: Jun Zhao <jun.zhao@intel.com>
Date: Tue, 2 Jan 2018 13:55:29 +0800
Subject: [PATCH] doc/codecs: Add missing documentation for hwaccel_flags.

document the hwaccel_flags option for decoding.

Signed-off-by: Jun Zhao <jun.zhao@intel.com>
---
 doc/codecs.texi | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

Ping? any comments?

On 2018/1/2 13:59, Jun Zhao wrote:

On Tue, 2 Jan 2018 13:59:12 +0800
Jun Zhao <mypopydev@gmail.com> wrote:

> From e030510864c28d4b17c8d1eb09ab00f274bf5dcc Mon Sep 17 00:00:00 2001
> From: Jun Zhao <jun.zhao@intel.com>
> Date: Tue, 2 Jan 2018 13:55:29 +0800
> Subject: [PATCH] doc/codecs: Add missing documentation for hwaccel_flags.
> 
> document the hwaccel_flags option for decoding.
> 
> Signed-off-by: Jun Zhao <jun.zhao@intel.com>
> ---
>  doc/codecs.texi | 27 +++++++++++++++++++++++++++
>  1 file changed, 27 insertions(+)
> 
> diff --git a/doc/codecs.texi b/doc/codecs.texi
> index 7e20374334..190f03b293 100644
> --- a/doc/codecs.texi
> +++ b/doc/codecs.texi
> @@ -1254,6 +1254,33 @@ ffprobe -dump_separator "
>  Maximum number of pixels per image. This value can be used to avoid out of
>  memory failures due to large images.
>  
> +@item hwaccel_flags @var{flags} (@emph{decoding,video})
> +Set hardware accelerated decoding flags. (if active)
> +
> +Possible values:
> +@table @samp
> +@item ignore_level
> +Ignore level, should be used for decoding even if the codec level used is unknown
> +or higher than the maximum supported level reported by the hardware driver.
> +
> +It's generally a good idea to pass this flag unless you have a specific
> +reason not to, as hardware tends to under-report supported levels.
> +@item allow_high_depth
> +Allow to output YUV pixel formats with a different chroma sampling than 4:2:0
> +and/or other than 8 bits per component
> +@item allow_profile_mismatch

This applies only to the legacy vdpau API. (The doxygen should probably
be updated about this.)

I'm not sure why stuff like this should be anywhere outside the doxygen
in the header files?

> +Attempt to decode anyway if hardware accelerated decoder's supported profiles do not
> +exactly match the stream.
> +
> +For example, this can be used to try to decode baseline profile H.264
> +streams in hardware - it will often succeed, because many streams marked
> +as baseline profile actually conform to constrained baseline profile.
> +
> +Warning: If the stream is actually not supported then the behaviour is
> +undefined, and may include returning entirely incorrect output
> +while indicating success.
> +@end table
> +
>  @item apply_cropping @var{bool} (@emph{decoding,video})
>  Enable cropping if cropping parameters are multiples of the required
>  alignment for the left and top parameters. If the alignment is not met the

On 2018/1/11 8:45, wm4 wrote:
> On Tue, 2 Jan 2018 13:59:12 +0800
> Jun Zhao <mypopydev@gmail.com> wrote:
>
>> From e030510864c28d4b17c8d1eb09ab00f274bf5dcc Mon Sep 17 00:00:00 2001
>> From: Jun Zhao <jun.zhao@intel.com>
>> Date: Tue, 2 Jan 2018 13:55:29 +0800
>> Subject: [PATCH] doc/codecs: Add missing documentation for hwaccel_flags.
>>
>> document the hwaccel_flags option for decoding.
>>
>> Signed-off-by: Jun Zhao <jun.zhao@intel.com>
>> ---
>>  doc/codecs.texi | 27 +++++++++++++++++++++++++++
>>  1 file changed, 27 insertions(+)
>>
>> diff --git a/doc/codecs.texi b/doc/codecs.texi
>> index 7e20374334..190f03b293 100644
>> --- a/doc/codecs.texi
>> +++ b/doc/codecs.texi
>> @@ -1254,6 +1254,33 @@ ffprobe -dump_separator "
>>  Maximum number of pixels per image. This value can be used to avoid out of
>>  memory failures due to large images.
>>  
>> +@item hwaccel_flags @var{flags} (@emph{decoding,video})
>> +Set hardware accelerated decoding flags. (if active)
>> +
>> +Possible values:
>> +@table @samp
>> +@item ignore_level
>> +Ignore level, should be used for decoding even if the codec level used is unknown
>> +or higher than the maximum supported level reported by the hardware driver.
>> +
>> +It's generally a good idea to pass this flag unless you have a specific
>> +reason not to, as hardware tends to under-report supported levels.
>> +@item allow_high_depth
>> +Allow to output YUV pixel formats with a different chroma sampling than 4:2:0
>> +and/or other than 8 bits per component
>> +@item allow_profile_mismatch
> This applies only to the legacy vdpau API. (The doxygen should probably
> be updated about this.)
I think VA-API decoder used the allow_profile_mismatch.
>
> I'm not sure why stuff like this should be anywhere outside the doxygen
> in the header files?
Now ffmpeg have a hwaccel_flags option, but this option didn't have a
docs in manpage,
so I think we can document this first.
>> +Attempt to decode anyway if hardware accelerated decoder's supported profiles do not
>> +exactly match the stream.
>> +
>> +For example, this can be used to try to decode baseline profile H.264
>> +streams in hardware - it will often succeed, because many streams marked
>> +as baseline profile actually conform to constrained baseline profile.
>> +
>> +Warning: If the stream is actually not supported then the behaviour is
>> +undefined, and may include returning entirely incorrect output
>> +while indicating success.
>> +@end table
>> +
>>  @item apply_cropping @var{bool} (@emph{decoding,video})
>>  Enable cropping if cropping parameters are multiples of the required
>>  alignment for the left and top parameters. If the alignment is not met the
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> ffmpeg-devel@ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel

On Thu, 11 Jan 2018 09:11:08 +0800
Jun Zhao <mypopydev@gmail.com> wrote:

> On 2018/1/11 8:45, wm4 wrote:
> > On Tue, 2 Jan 2018 13:59:12 +0800
> > Jun Zhao <mypopydev@gmail.com> wrote:
> >  
> >> From e030510864c28d4b17c8d1eb09ab00f274bf5dcc Mon Sep 17 00:00:00 2001
> >> From: Jun Zhao <jun.zhao@intel.com>
> >> Date: Tue, 2 Jan 2018 13:55:29 +0800
> >> Subject: [PATCH] doc/codecs: Add missing documentation for hwaccel_flags.
> >>
> >> document the hwaccel_flags option for decoding.
> >>
> >> Signed-off-by: Jun Zhao <jun.zhao@intel.com>
> >> ---
> >>  doc/codecs.texi | 27 +++++++++++++++++++++++++++
> >>  1 file changed, 27 insertions(+)
> >>
> >> diff --git a/doc/codecs.texi b/doc/codecs.texi
> >> index 7e20374334..190f03b293 100644
> >> --- a/doc/codecs.texi
> >> +++ b/doc/codecs.texi
> >> @@ -1254,6 +1254,33 @@ ffprobe -dump_separator "
> >>  Maximum number of pixels per image. This value can be used to avoid out of
> >>  memory failures due to large images.
> >>  
> >> +@item hwaccel_flags @var{flags} (@emph{decoding,video})
> >> +Set hardware accelerated decoding flags. (if active)
> >> +
> >> +Possible values:
> >> +@table @samp
> >> +@item ignore_level
> >> +Ignore level, should be used for decoding even if the codec level used is unknown
> >> +or higher than the maximum supported level reported by the hardware driver.
> >> +
> >> +It's generally a good idea to pass this flag unless you have a specific
> >> +reason not to, as hardware tends to under-report supported levels.
> >> +@item allow_high_depth
> >> +Allow to output YUV pixel formats with a different chroma sampling than 4:2:0
> >> +and/or other than 8 bits per component
> >> +@item allow_profile_mismatch  
> > This applies only to the legacy vdpau API. (The doxygen should probably
> > be updated about this.)  
> I think VA-API decoder used the allow_profile_mismatch.

I meant the allow_high_depth flag.

On 2018/1/11 9:26, wm4 wrote:
> On Thu, 11 Jan 2018 09:11:08 +0800
> Jun Zhao <mypopydev@gmail.com> wrote:
>
>> On 2018/1/11 8:45, wm4 wrote:
>>> On Tue, 2 Jan 2018 13:59:12 +0800
>>> Jun Zhao <mypopydev@gmail.com> wrote:
>>>  
>>>> From e030510864c28d4b17c8d1eb09ab00f274bf5dcc Mon Sep 17 00:00:00 2001
>>>> From: Jun Zhao <jun.zhao@intel.com>
>>>> Date: Tue, 2 Jan 2018 13:55:29 +0800
>>>> Subject: [PATCH] doc/codecs: Add missing documentation for hwaccel_flags.
>>>>
>>>> document the hwaccel_flags option for decoding.
>>>>
>>>> Signed-off-by: Jun Zhao <jun.zhao@intel.com>
>>>> ---
>>>>  doc/codecs.texi | 27 +++++++++++++++++++++++++++
>>>>  1 file changed, 27 insertions(+)
>>>>
>>>> diff --git a/doc/codecs.texi b/doc/codecs.texi
>>>> index 7e20374334..190f03b293 100644
>>>> --- a/doc/codecs.texi
>>>> +++ b/doc/codecs.texi
>>>> @@ -1254,6 +1254,33 @@ ffprobe -dump_separator "
>>>>  Maximum number of pixels per image. This value can be used to avoid out of
>>>>  memory failures due to large images.
>>>>  
>>>> +@item hwaccel_flags @var{flags} (@emph{decoding,video})
>>>> +Set hardware accelerated decoding flags. (if active)
>>>> +
>>>> +Possible values:
>>>> +@table @samp
>>>> +@item ignore_level
>>>> +Ignore level, should be used for decoding even if the codec level used is unknown
>>>> +or higher than the maximum supported level reported by the hardware driver.
>>>> +
>>>> +It's generally a good idea to pass this flag unless you have a specific
>>>> +reason not to, as hardware tends to under-report supported levels.
>>>> +@item allow_high_depth
>>>> +Allow to output YUV pixel formats with a different chroma sampling than 4:2:0
>>>> +and/or other than 8 bits per component
>>>> +@item allow_profile_mismatch  
>>> This applies only to the legacy vdpau API. (The doxygen should probably
>>> be updated about this.)  
>> I think VA-API decoder used the allow_profile_mismatch.
> I meant the allow_high_depth flag.
Got it， thanks the  clarify.
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