[FFmpeg-devel] [PATCH 1/2] lavf: allow setting AVStream.discard as an AVOption

[James Almer]

On 12/19/2023 7:41 AM, Anton Khirnov wrote:
> Quoting James Almer (2023-12-18 20:30:47)
>> On 12/18/2023 4:19 PM, Anton Khirnov wrote:
>>> ---
>>>    libavformat/options.c | 10 ++++++++++
>>>    1 file changed, 10 insertions(+)
>>>
>>> diff --git a/libavformat/options.c b/libavformat/options.c
>>> index bf6113ca95..cc89dd6c72 100644
>>> --- a/libavformat/options.c
>>> +++ b/libavformat/options.c
>>> @@ -229,6 +229,16 @@ static const AVOption stream_options[] = {
>>>            { "metadata",           .type = AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_METADATA          },    .unit = "disposition" },
>>>            { "dependent",          .type = AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_DEPENDENT         },    .unit = "disposition" },
>>>            { "still_image",        .type = AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_STILL_IMAGE       },    .unit = "disposition" },
>>> +
>>> +    { "discard", NULL, offsetof(AVStream, discard), AV_OPT_TYPE_INT, { .i64 = AVDISCARD_DEFAULT }, INT_MIN, INT_MAX,
>>> +        .flags = AV_OPT_FLAG_DECODING_PARAM, .unit = "avdiscard" },
>>> +        { "none",               .type = AV_OPT_TYPE_CONST, {.i64 = AVDISCARD_NONE     }, .unit = "avdiscard" },
>>> +        { "default",            .type = AV_OPT_TYPE_CONST, {.i64 = AVDISCARD_DEFAULT  }, .unit = "avdiscard" },
>>> +        { "noref",              .type = AV_OPT_TYPE_CONST, {.i64 = AVDISCARD_NONREF   }, .unit = "avdiscard" },
>>> +        { "bidir",              .type = AV_OPT_TYPE_CONST, {.i64 = AVDISCARD_BIDIR    }, .unit = "avdiscard" },
>>> +        { "nointra",            .type = AV_OPT_TYPE_CONST, {.i64 = AVDISCARD_NONINTRA }, .unit = "avdiscard" },
>>> +        { "nokey",              .type = AV_OPT_TYPE_CONST, {.i64 = AVDISCARD_NONKEY   }, .unit = "avdiscard" },
>>> +        { "all",                .type = AV_OPT_TYPE_CONST, {.i64 = AVDISCARD_ALL      }, .unit = "avdiscard" },
>>>        { NULL }
>>>    };
>>
>> Should be ok.
>>
>> Maybe also add "id" like i did for AVStreamGroup while at it.
> 
> The problem with id is how to flag it - it's read-only for demuxing and
> user-settable for muxing.

Wouldn't the AV_OPT_FLAG_ENCODING_PARAM flag be enough for the CLI to 
reject it for demuxing cases?