[FFmpeg-devel] [PATCH] ffmpeg: Add option to force a specific decode format

[Michael Niedermayer]

On Sun, Nov 11, 2018 at 02:54:41PM +0000, Mark Thompson wrote:
> Fixes #7519.
> ---
> I've had this lying around for a bit with intent to use it to support non-hwaccel hardware decoders (in particular, v4l2m2m), but it actually fixes the force-hwaccel use-case too in a sensible way.
> 
> 
>  doc/ffmpeg.texi      | 12 ++++++++++++
>  fftools/ffmpeg.c     |  4 ++++
>  fftools/ffmpeg.h     |  4 ++++
>  fftools/ffmpeg_opt.c | 15 +++++++++++++++
>  4 files changed, 35 insertions(+)
> 
> diff --git a/doc/ffmpeg.texi b/doc/ffmpeg.texi
> index 3717f22d42..9f9e693898 100644
> --- a/doc/ffmpeg.texi
> +++ b/doc/ffmpeg.texi
> @@ -920,6 +920,18 @@ would be more efficient.
>  When doing stream copy, copy also non-key frames found at the
>  beginning.
>  
> + at item -decode_format[:@var{stream_specifier}] @var{pixfmt} (@emph{input,per-stream})
> +Set the output format to be used by the decoder for this stream.  If the
> +decoder does not natively support this format for the input stream then
> +decoding will fail rather than continuing with a different format.
> +
> +In general this should not be set - the decoder will select an output
> +format based on the input stream parameters and available components, and
> +that will be automatically converted to whatever the output requires.  It
> +may be useful to force a hardware decoder supporting output in multiple
> +different memory types to pick the desired one, or to ensure that a
> +hardware decoder is used when software fallback is also available.
> +
>  @item -init_hw_device @var{type}[=@var{name}][:@var{device}[, at var{key=value}...]]
>  Initialise a new hardware device of type @var{type} called @var{name}, using the
>  given device parameters.
> diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
> index 38c21e944a..73bed55e4d 100644
> --- a/fftools/ffmpeg.c
> +++ b/fftools/ffmpeg.c
> @@ -2800,6 +2800,10 @@ static enum AVPixelFormat get_format(AVCodecContext *s, const enum AVPixelFormat
>          const AVCodecHWConfig  *config = NULL;
>          int i;
>  
> +        if (ist->decode_format != AV_PIX_FMT_NONE &&
> +            ist->decode_format != *p)
> +            continue;
> +
>          if (!(desc->flags & AV_PIX_FMT_FLAG_HWACCEL))
>              break;
>  
> diff --git a/fftools/ffmpeg.h b/fftools/ffmpeg.h
> index eb1eaf6363..88e0aa60ea 100644
> --- a/fftools/ffmpeg.h
> +++ b/fftools/ffmpeg.h
> @@ -125,6 +125,8 @@ typedef struct OptionsContext {
>      int        nb_ts_scale;
>      SpecifierOpt *dump_attachment;
>      int        nb_dump_attachment;
> +    SpecifierOpt *decode_formats;
> +    int        nb_decode_formats;
>      SpecifierOpt *hwaccels;
>      int        nb_hwaccels;
>      SpecifierOpt *hwaccel_devices;

> @@ -334,6 +336,8 @@ typedef struct InputStream {
>      int top_field_first;
>      int guess_layout_max;
>  
> +    enum AVPixelFormat decode_format;
> +

I think this should be a list and not a single format
either way, the patch LGTM

thx


[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In a rich man's house there is no place to spit but his face.
-- Diogenes of Sinope
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