The AMLogic meson V4L2 M2M I'm developping (https://github.com/Elyotna/linux)
can fare with only one OUTPUT buffer for data input.
Granted, only 1 CAPTURE buffer is probably not going to cut it, but still,
I don't see the reason behind restricting the FFmpeg user to try with 1 (in
the end the driver will adjust the min/max buffers anyway).
2018-04-05 22:14 GMT+02:00 Jorge Ramirez-Ortiz <jrami...@baylibre.com>:
> On 04/05/2018 06:42 PM, Maxime Jourdan wrote:
>
>> Reduce the minimum amount of CAPTURE and OUTPUT buffers to 1.
>>
>
> makes sense to me if that is indeed the case.
> could you provide a real life use case?
>
>
>
>> There are drivers that may work with such drastic settings,
>> and FFmpeg doesn't complain.
>> ---
>> libavcodec/v4l2_m2m.h | 2 +-
>> libavcodec/v4l2_m2m_dec.c | 2 +-
>> 2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/libavcodec/v4l2_m2m.h b/libavcodec/v4l2_m2m.h
>> index 452bf0d9bc..68e4e5d6c6 100644
>> --- a/libavcodec/v4l2_m2m.h
>> +++ b/libavcodec/v4l2_m2m.h
>> @@ -38,7 +38,7 @@
>> #define V4L_M2M_DEFAULT_OPTS \
>> { "num_output_buffers", "Number of buffers in the output context",\
>> - OFFSET(num_output_buffers), AV_OPT_TYPE_INT, { .i64 = 16 }, 6,
>> INT_MAX, FLAGS }
>> + OFFSET(num_output_buffers), AV_OPT_TYPE_INT, { .i64 = 16 }, 1,
>> INT_MAX, FLAGS }
>> typedef struct V4L2m2mContext {
>> char devname[PATH_MAX];
>> diff --git a/libavcodec/v4l2_m2m_dec.c b/libavcodec/v4l2_m2m_dec.c
>> index bca45be148..5196680bbb 100644
>> --- a/libavcodec/v4l2_m2m_dec.c
>> +++ b/libavcodec/v4l2_m2m_dec.c
>> @@ -198,7 +198,7 @@ static av_cold int v4l2_decode_init(AVCodecContext
>> *avctx)
>> static const AVOption options[] = {
>> V4L_M2M_DEFAULT_OPTS,
>> { "num_capture_buffers", "Number of buffers in the capture context",
>> - OFFSET(num_capture_buffers), AV_OPT_TYPE_INT, {.i64 = 20}, 20,
>> INT_MAX, FLAGS },
>> + OFFSET(num_capture_buffers), AV_OPT_TYPE_INT, {.i64 = 20}, 1,
>> INT_MAX, FLAGS },
>> { NULL},
>> };
>> --
>> 2.16.2
>>
>
>
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