[FFmpeg-devel] [PATCH] encoders.texi: update libvpx documentation

James Zern jzern at google.com
Fri Jun 12 21:38:42 CEST 2015


On Fri, Jun 12, 2015 at 5:58 AM, Stefano Sabatini <stefasab at gmail.com> wrote:
> On date Wednesday 2015-06-10 20:58:33 -0700, James Zern encoded:
>> [...]
>> - at item speed
>> - at code{VP8E_SET_CPUUSED}
>> + at item speed, cpu-used (@emph{cpu-used})
>
>> +Quality/Speed ratio modifier.
>
> Nit: Set quality/speed ...
>
> In general, a verbal form is favored ("Set number of foos in the bar.",
> rather than "number of foos in the bar").
>

Sorry about that, a bit of this was lazily copied from the terse help
output. Do you have a preference for formatting in that case?

>>
>> - at item nr
>> - at code{VP8E_SET_NOISE_SENSITIVITY}
>> + at item nr (@emph{noise-sensitivity})
>>
>> - at item mb_threshold
>> - at code{VP8E_SET_STATIC_THRESHOLD}
>> + at item static-thresh
>
>> +A change threshold on blocks below which they will be skipped by the encoder.
>
> Nit: Set a change threshold ...
>

Done.

>
>> - at item slices
>> - at code{VP8E_SET_TOKEN_PARTITIONS}
>> + at item slices (@emph{token-parts})
>> +Note that FFmpeg's @option{slices} option gives the total number of partitions,
>> +while @command{vpxenc}'s @option{token-parts} is given as
>> + at code{log2(partitions)}.
>>
>>  @item max-intra-rate
>> - at code{VP8E_SET_MAX_INTRA_BITRATE_PCT}
>> +Maximum I-frame bitrate (pct) 0=unlimited.
>
> Set maximum ...
>
> Also
> Maximum I-frame bitrate (pct) 0=unlimited.
> is not a meaningful English sentence, add something like:
>
> A value of 0 means unlimited.
>
> (I don't know what "pct" is).
>

All done.

>>
>>  @item force_key_frames
>>  @code{VPX_EFLAG_FORCE_KF}
>>
>>  @item Alternate reference frame related
>>  @table @option
>> - at item vp8flags altref
>> - at code{VP8E_SET_ENABLEAUTOALTREF}
>> - at item @var{arnr_max_frames}
>> - at code{VP8E_SET_ARNR_MAXFRAMES}
>> - at item @var{arnr_type}
>> - at code{VP8E_SET_ARNR_TYPE}
>> - at item @var{arnr_strength}
>> - at code{VP8E_SET_ARNR_STRENGTH}
>> - at item @var{rc_lookahead}
>> -g_lag_in_frames
>> - at end table
>> -
>> - at item vp8flags error_resilient
>> -g_error_resilient
>> -
>> - at item aq_mode
>> - at code{VP9E_SET_AQ_MODE}
>> + at item auto-alt-ref
>> +Enable use of alternate reference frames (2-pass only).
>
>> + at item arnr-max-frames
>> +altref noise reduction max frame count.
>
> Set altref ...
>

Done.

>> + at item arnr-type
>> +altref noise reduction filter type: backward, forward, centered.
>
> Set altref ...
>

Done.

>> + at item arnr-strength
>> +altref noise reduction filter strength.
>
> Set altref ...
>

Done.

>> + at item rc-lookahead, lag-in-frames (@emph{lag-in-frames})
>> +Set number of frames to look ahead for frametype and ratecontrol.
>> + at end table
>> +
>> + at item error-resilient
>> +Enable error resiliency features.
>> +
>> + at item VP9-specific options
>> + at table @option
>
>> + at item lossless
>> +Lossless mode.
>
> Set lossless mode?
>

Done.

>> + at item tile-columns
>> +Number of tile columns to use, log2.
>
> Set number of tile columns to use. What "log2" means in this context?
>
>> + at item tile-rows
>> +Number of tile rows to use, log2.
>
> Ditto
>

I added a few examples. I would have preferred that this was
represented as a natural value (hi Ronald!), it's not very intuitive
for a user.

>> + at item frame-parallel
>> +Enable frame parallel decodability features.
>> + at item aq-mode
>
>> +Adaptive quantization mode (0: off (default), 1: variance 2: complexity, 3:
>> +cyclic refresh).
>
> Set adaptive ...
>

Done.

>
> LGTM otherwise, thanks.
> --
> FFmpeg = Friendly and Forgiving Multimedia Pitiless Easy Gymnast
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