[FFmpeg-devel] [PATCH] avformat/http: Add short_seek_size option

[James Almer]

On 11/15/2021 12:52 PM, Derek Buitenhuis wrote:
> In 45bfe8b838275235412777dd430206d9a24eb3ee, short_seek_threshold was removed
> from the public AVIO struct. Although this option was private and not intended
> to be used by public API users, it was nonetheless, because it provided functionality
> that could otherwise not be gained via public API.
> 
> This was especially important for networked I/O like HTTP, where the internal
> size for lavf could be way to small depending on the specifics of a user's
> usecase, such as reading interlavd media files from cloud storage.
> 
> Add an AVOption to make this functionality accessible to the HTTP client.
> 
> Signed-off-by: Derek Buitenhuis <derek.buitenhuis at gmail.com>
> ---
> Same as last version but I'm marking it as non-RFC. I think I prefer the AVOption approach.
> 
> Comments welcome.

Don't forget to bump micro before you push.

> ---
>   libavformat/http.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/libavformat/http.c b/libavformat/http.c
> index 476b9a8456..0dc1ce0f43 100644
> --- a/libavformat/http.c
> +++ b/libavformat/http.c
> @@ -126,6 +126,7 @@ typedef struct HTTPContext {
>       int is_multi_client;
>       HandshakeState handshake_step;
>       int is_connected_server;
> +    int short_seek_size;
>   } HTTPContext;
>   
>   #define OFFSET(x) offsetof(HTTPContext, x)
> @@ -167,6 +168,7 @@ static const AVOption options[] = {
>       { "listen", "listen on HTTP", OFFSET(listen), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 2, D | E },
>       { "resource", "The resource requested by a client", OFFSET(resource), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, E },
>       { "reply_code", "The http status code to return to a client", OFFSET(reply_code), AV_OPT_TYPE_INT, { .i64 = 200}, INT_MIN, 599, E},
> +    { "short_seek_size", "Threshold to favor readahead over seek.", OFFSET(short_seek_size), AV_OPT_TYPE_INT, { .i64 = -1 }, 1, INT64_MAX, D },

-1 default when the valid range is 1 to INT64_MAX?

>       { NULL }
>   };
>   
> @@ -1842,6 +1844,8 @@ static int http_get_file_handle(URLContext *h)
>   static int http_get_short_seek(URLContext *h)
>   {
>       HTTPContext *s = h->priv_data;
> +    if (s->short_seek_size >= 1)
> +        return s->short_seek_size;
>       return ffurl_get_short_seek(s->hd);
>   }
>   
>