[FFmpeg-devel] [PATCH 2/3] decklink: new option 'format' to set video format by fourCC

[Marton Balint]

On Thu, 16 Mar 2017, Matthias Hunstock wrote:

> ---
> libavdevice/decklink_common.cpp | 22 ++++++++++++++++++----
> libavdevice/decklink_common_c.h |  1 +
> libavdevice/decklink_dec.cpp    |  2 +-
> libavdevice/decklink_dec_c.c    |  1 +
> 4 files changed, 21 insertions(+), 5 deletions(-)
>
> diff --git a/libavdevice/decklink_common.cpp b/libavdevice/decklink_common.cpp
> index 131d186..548bf3b 100644
> --- a/libavdevice/decklink_common.cpp
> +++ b/libavdevice/decklink_common.cpp
> @@ -143,6 +143,18 @@ static DECKLINK_BOOL field_order_eq(enum AVFieldOrder field_order, BMDFieldDomin
>     return false;
> }
> 
> +static DECKLINK_BOOL fourcc_eq(char *fourcc_string, BMDDisplayMode fourcc)
> +{
> +    BMDDisplayMode fourcc_converted = 0;
> +    if (!fourcc_string) return false;
> +    if (!strcmp(fourcc_string, "pal") && fourcc == 0x70616C20) return true;
> +    if (strlen(fourcc_string) < 4) return false;
> +    fourcc_converted = ((uint8_t) fourcc_string[0] << 24) | ((uint8_t) fourcc_string[1] << 16) |
> +        ((uint8_t) fourcc_string[2] << 8) | ((uint8_t) fourcc_string[3]);
> +    if (fourcc_converted == fourcc) return true;
> +    return false;
> +}

I think I'd use a little different approach. Instead of a separate _eq 
function, I'd transfrom the fourcc string to an int32 by padding it with 4 
spaces, then use AV_RL32(padded_fourcc) to get an actual int32. I can now 
simply compare this to BMDDisplayMode.

> +
> int ff_decklink_set_format(AVFormatContext *avctx,
>                                int width, int height,
>                                int tb_num, int tb_den,
> @@ -157,8 +169,8 @@ int ff_decklink_set_format(AVFormatContext *avctx,
>     int i = 1;
>     HRESULT res;
> 
> -    av_log(avctx, AV_LOG_DEBUG, "Trying to find mode for frame size %dx%d, frame timing %d/%d, field order %d, direction %d, mode number %d\n",
> -        width, height, tb_num, tb_den, field_order, direction, num);
> +    av_log(avctx, AV_LOG_DEBUG, "Trying to find mode for frame size %dx%d, frame timing %d/%d, field order %d, direction %d, mode number %d, mode fourCC %s\n",
> +        width, height, tb_num, tb_den, field_order, direction, num, cctx->format);

cctx->format ? cctx->format : "(unset)"

>
>     if (ctx->duplex_mode) {
>         DECKLINK_BOOL duplex_supported = false;
> @@ -202,6 +214,7 @@ int ff_decklink_set_format(AVFormatContext *avctx,
>         int bmd_width  = mode->GetWidth();
>         int bmd_height = mode->GetHeight();
>         BMDFieldDominance bmd_field_dominance = mode->GetFieldDominance();
> +        BMDDisplayMode bmd_mode = mode->GetDisplayMode();
>
>         mode->GetFrameRate(&bmd_tb_num, &bmd_tb_den);
>         AVRational mode_tb = av_make_q(bmd_tb_num, bmd_tb_den);
> @@ -209,8 +222,9 @@ int ff_decklink_set_format(AVFormatContext *avctx,
>         if ((bmd_width == width &&
>              bmd_height == height &&
>              !av_cmp_q(mode_tb, target_tb) &&
> -             field_order_eq(field_order, bmd_field_dominance)) || i == num) {
> -            ctx->bmd_mode   = mode->GetDisplayMode();
> +             field_order_eq(field_order, bmd_field_dominance))
> +             || i == num || fourcc_eq(cctx->format, bmd_mode)) {
> +            ctx->bmd_mode   = bmd_mode;
>             ctx->bmd_width  = bmd_width;
>             ctx->bmd_height = bmd_height;
>             ctx->bmd_tb_den = bmd_tb_den;
> diff --git a/libavdevice/decklink_common_c.h b/libavdevice/decklink_common_c.h
> index d565631..161a48a 100644
> --- a/libavdevice/decklink_common_c.h
> +++ b/libavdevice/decklink_common_c.h
> @@ -47,6 +47,7 @@ struct decklink_cctx {
>     int audio_input;
>     int video_input;
>     int draw_bars;
> +    char *format;
> };
> 
> #endif /* AVDEVICE_DECKLINK_COMMON_C_H */
> diff --git a/libavdevice/decklink_dec.cpp b/libavdevice/decklink_dec.cpp
> index 7df841b..5948888 100644
> --- a/libavdevice/decklink_dec.cpp
> +++ b/libavdevice/decklink_dec.cpp
> @@ -539,7 +539,7 @@ av_cold int ff_decklink_read_header(AVFormatContext *avctx)
>         goto error;
>     }
> 
> -    if (mode_num > 0) {
> +    if (mode_num > 0 || cctx->format) {
>         if (ff_decklink_set_format(avctx, DIRECTION_IN, mode_num) < 0) {
>             av_log(avctx, AV_LOG_ERROR, "Could not set mode %d for %s\n", mode_num, fname);
>             ret = AVERROR(EIO);
> diff --git a/libavdevice/decklink_dec_c.c b/libavdevice/decklink_dec_c.c
> index 31818d2..07da7cc 100644
> --- a/libavdevice/decklink_dec_c.c
> +++ b/libavdevice/decklink_dec_c.c
> @@ -31,6 +31,7 @@
> static const AVOption options[] = {
>     { "list_devices", "list available devices"  , OFFSET(list_devices), AV_OPT_TYPE_INT   , { .i64 = 0   }, 0, 1, DEC },
>     { "list_formats", "list supported formats"  , OFFSET(list_formats), AV_OPT_TYPE_INT   , { .i64 = 0   }, 0, 1, DEC },
> +    { "format",       "set format by fourcc"    , OFFSET(format),       AV_OPT_TYPE_STRING, { .str = NULL}, 3, 4, DEC },
>     { "bm_v210",      "v210 10 bit per channel" , OFFSET(v210),         AV_OPT_TYPE_INT   , { .i64 = 0   }, 0, 1, DEC },
>     { "teletext_lines", "teletext lines bitmask", OFFSET(teletext_lines), AV_OPT_TYPE_INT64, { .i64 = 0   }, 0, 0x7ffffffffLL, DEC, "teletext_lines"},
>     { "standard",     NULL,                                           0,  AV_OPT_TYPE_CONST, { .i64 = 0x7fff9fffeLL}, 0, 0,    DEC, "teletext_lines"},
> -- 
> 2.1.4
>

Regards,
Marton