[FFmpeg-devel] [PATCH v2] ffmpeg: add -fpsmin to clamp output framerate

Gyan Doshi ffmpeg at gyani.pro
Sat May 15 16:11:51 EEST 2021


I'll review this in a few days.

On 2021-05-11 21:42, Matthias Neugebauer wrote:
> Add -fpsmin analogously to -fpsmax for setting a lower bound to the
> auto-set frame rate.
>
> Signed-off-by: Matthias Neugebauer <mtneug at mailbox.org>
> ---
> doc/ffmpeg.texi      |  7 +++++++
> fftools/ffmpeg.c     |  8 +++++++-
> fftools/ffmpeg.h     |  3 +++
> fftools/ffmpeg_opt.c | 26 +++++++++++++++++++++++---
> 4 files changed, 40 insertions(+), 4 deletions(-)
>
> diff --git a/doc/ffmpeg.texi b/doc/ffmpeg.texi
> index 9feabe6517..5576508347 100644
> --- a/doc/ffmpeg.texi
> +++ b/doc/ffmpeg.texi
> @@ -862,6 +862,13 @@ Clamps output frame rate when output framerate is auto-set and is higher than th
> Useful in batch processing or when input framerate is wrongly detected as very high.
> It cannot be set together with @code{-r}. It is ignored during streamcopy.
>
> + at item -fpsmin[:@var{stream_specifier}] @var{fps} (@emph{output,per-stream})
> +Set minimum frame rate (Hz value, fraction or abbreviation).
> +
> +Clamps output frame rate when output framerate is auto-set and is lower than this value.
> +Useful in batch processing or when input framerate is wrongly detected as very low.
> +It cannot be set together with @code{-r}. It is ignored during streamcopy.
> +
> @item -s[:@var{stream_specifier}] @var{size} (@emph{input/output,per-stream})
> Set frame size.
>
> diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
> index 3ad11452da..696ba7d730 100644
> --- a/fftools/ffmpeg.c
> +++ b/fftools/ffmpeg.c
> @@ -3390,7 +3390,8 @@ static int init_output_stream_encode(OutputStream *ost, AVFrame *frame)
>               ost->frame_rate = ist->framerate;
>           if (ist && !ost->frame_rate.num)
>               ost->frame_rate = ist->st->r_frame_rate;
> -        if (ist && !ost->frame_rate.num && !ost->max_frame_rate.num) {
> +        if (ist && !ost->frame_rate.num && !ost->max_frame_rate.num && !ost->min_frame_rate.num)
> +        {
>               ost->frame_rate = (AVRational){25, 1};
>               av_log(NULL, AV_LOG_WARNING,
>                      "No information "
> @@ -3400,6 +3401,11 @@ static int init_output_stream_encode(OutputStream *ost, AVFrame *frame)
>                      ost->file_index, ost->index);
>           }
>
> +        if (ost->min_frame_rate.num &&
> +            (av_q2d(ost->frame_rate) < av_q2d(ost->min_frame_rate) ||
> +            !ost->frame_rate.den))
> +            ost->frame_rate = ost->min_frame_rate;
> +
>           if (ost->max_frame_rate.num &&
>               (av_q2d(ost->frame_rate) > av_q2d(ost->max_frame_rate) ||
>               !ost->frame_rate.den))
> diff --git a/fftools/ffmpeg.h b/fftools/ffmpeg.h
> index 606f2afe0c..515d0c7a46 100644
> --- a/fftools/ffmpeg.h
> +++ b/fftools/ffmpeg.h
> @@ -110,6 +110,8 @@ typedef struct OptionsContext {
>       int        nb_frame_rates;
>       SpecifierOpt *max_frame_rates;
>       int        nb_max_frame_rates;
> +    SpecifierOpt *min_frame_rates;
> +    int        nb_min_frame_rates;
>       SpecifierOpt *frame_sizes;
>       int        nb_frame_sizes;
>       SpecifierOpt *frame_pix_fmts;
> @@ -486,6 +488,7 @@ typedef struct OutputStream {
>       /* video only */
>       AVRational frame_rate;
>       AVRational max_frame_rate;
> +    AVRational min_frame_rate;
>       int is_cfr;
>       int force_fps;
>       int top_field_first;
> diff --git a/fftools/ffmpeg_opt.c b/fftools/ffmpeg_opt.c
> index 849d24b16d..b0d7550ce6 100644
> --- a/fftools/ffmpeg_opt.c
> +++ b/fftools/ffmpeg_opt.c
> @@ -56,6 +56,7 @@ static const char *const opt_name_audio_channels[]            = {"ac", NULL};
> static const char *const opt_name_audio_sample_rate[]         = {"ar", NULL};
> static const char *const opt_name_frame_rates[]               = {"r", NULL};
> static const char *const opt_name_max_frame_rates[]           = {"fpsmax", NULL};
> +static const char *const opt_name_min_frame_rates[]           = {"fpsmin", NULL};
> static const char *const opt_name_frame_sizes[]               = {"s", NULL};
> static const char *const opt_name_frame_pix_fmts[]            = {"pix_fmt", NULL};
> static const char *const opt_name_ts_scale[]                  = {"itsscale", NULL};
> @@ -1694,7 +1695,7 @@ static OutputStream *new_video_stream(OptionsContext *o, AVFormatContext *oc, in
>       AVStream *st;
>       OutputStream *ost;
>       AVCodecContext *video_enc;
> -    char *frame_rate = NULL, *max_frame_rate = NULL, *frame_aspect_ratio = NULL;
> +    char *frame_rate = NULL, *max_frame_rate = NULL, *min_frame_rate = NULL, *frame_aspect_ratio = NULL;
>
>       ost = new_output_stream(o, oc, AVMEDIA_TYPE_VIDEO, source_index);
>       st  = ost->st;
> @@ -1712,14 +1713,30 @@ static OutputStream *new_video_stream(OptionsContext *o, AVFormatContext *oc, in
>           exit_program(1);
>       }
>
> +    MATCH_PER_STREAM_OPT(min_frame_rates, str, min_frame_rate, oc, st);
> +    if (min_frame_rate && av_parse_video_rate(&ost->min_frame_rate, min_frame_rate) < 0) {
> +        av_log(NULL, AV_LOG_FATAL, "Invalid minimum framerate value: %s\n", min_frame_rate);
> +        exit_program(1);
> +    }
> +
>       if (frame_rate && max_frame_rate) {
>           av_log(NULL, AV_LOG_ERROR, "Only one of -fpsmax and -r can be set for a stream.\n");
>           exit_program(1);
>       }
>
> -    if ((frame_rate || max_frame_rate) &&
> +    if (frame_rate && min_frame_rate) {
> +        av_log(NULL, AV_LOG_ERROR, "Only one of -fpsmin and -r can be set for a stream.\n");
> +        exit_program(1);
> +    }
> +
> +    if (min_frame_rate && max_frame_rate && av_q2d(ost->min_frame_rate) > av_q2d(ost->max_frame_rate)) {
> +        av_log(NULL, AV_LOG_ERROR, "-fpsmin cannot be larger then -fpsmax.\n");
> +        exit_program(1);
> +    }
> +
> +    if ((frame_rate || max_frame_rate || min_frame_rate) &&
>           video_sync_method == VSYNC_PASSTHROUGH)
> -        av_log(NULL, AV_LOG_ERROR, "Using -vsync 0 and -r/-fpsmax can produce invalid output files\n");
> +        av_log(NULL, AV_LOG_ERROR, "Using -vsync 0 and -r/-fpsmax/-fpsmin can produce invalid output files\n");
>
>       MATCH_PER_STREAM_OPT(frame_aspect_ratios, str, frame_aspect_ratio, oc, st);
>       if (frame_aspect_ratio) {
> @@ -3609,6 +3626,9 @@ const OptionDef options[] = {
>       { "fpsmax",       OPT_VIDEO | HAS_ARG  | OPT_STRING | OPT_SPEC |
>                         OPT_OUTPUT,                                                { .off = OFFSET(max_frame_rates) },
>           "set max frame rate (Hz value, fraction or abbreviation)", "rate" },
> +    { "fpsmin",       OPT_VIDEO | HAS_ARG  | OPT_STRING | OPT_SPEC |
> +                      OPT_OUTPUT,                                                { .off = OFFSET(min_frame_rates) },
> +        "set min frame rate (Hz value, fraction or abbreviation)", "rate" },
>       { "s",            OPT_VIDEO | HAS_ARG | OPT_SUBTITLE | OPT_STRING | OPT_SPEC |
>                         OPT_INPUT | OPT_OUTPUT,                                    { .off = OFFSET(frame_sizes) },
>           "set frame size (WxH or abbreviation)", "size" },



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