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

James Almer jamrial at gmail.com
Wed Feb 3 06:17:19 EET 2021


On 2/3/2021 1:08 AM, Gyan Doshi wrote:
> Plan to push this in a day.

It's been a day since you submitted this patch, so you can give people 
some more time to look at it. There's no hurry.

> 
> On 01-02-2021 06:52 pm, Gyan Doshi wrote:
>> Useful when encoding in batch or with aberrant inputs.
>> ---
>>   doc/ffmpeg.texi      |  7 +++++++
>>   fftools/ffmpeg.c     |  7 ++++++-
>>   fftools/ffmpeg.h     |  3 +++
>>   fftools/ffmpeg_opt.c | 24 +++++++++++++++++++++---
>>   4 files changed, 37 insertions(+), 4 deletions(-)
>>
>> Forgot to nullify rmax with r set.
>>
>> diff --git a/doc/ffmpeg.texi b/doc/ffmpeg.texi
>> index 8eb012b7c0..7726f25082 100644
>> --- a/doc/ffmpeg.texi
>> +++ b/doc/ffmpeg.texi
>> @@ -759,6 +759,13 @@ If in doubt use @option{-framerate} instead of 
>> the input option @option{-r}.
>>   As an output option, duplicate or drop input frames to achieve 
>> constant output
>>   frame rate @var{fps}.
>> + at item -rmax[:@var{stream_specifier}] @var{fps} 
>> (@emph{output,per-stream})
>> +Set maximum frame rate (Hz value, fraction or abbreviation).
>> +
>> +Clamps output frame rate when output framerate is auto-set and is 
>> higher than this value.
>> +Useful in batch processing or when input framerate is wrongly 
>> detected as very high.
>> +Ignored when either @code{-r} is set or 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 d7c833be63..add5a3e505 100644
>> --- a/fftools/ffmpeg.c
>> +++ b/fftools/ffmpeg.c
>> @@ -3376,7 +3376,7 @@ 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) {
>> +        if (ist && !ost->frame_rate.num && !ost->max_frame_rate.num) {
>>               ost->frame_rate = (AVRational){25, 1};
>>               av_log(NULL, AV_LOG_WARNING,
>>                      "No information "
>> @@ -3386,6 +3386,11 @@ static int 
>> init_output_stream_encode(OutputStream *ost, AVFrame *frame)
>>                      ost->file_index, ost->index);
>>           }
>> +        if (ost->max_frame_rate.num &&
>> +            (av_q2d(ost->frame_rate) > av_q2d(ost->max_frame_rate) ||
>> +            !ost->frame_rate.den))
>> +            ost->frame_rate = ost->max_frame_rate;
>> +
>>           if (ost->enc->supported_framerates && !ost->force_fps) {
>>               int idx = av_find_nearest_q_idx(ost->frame_rate, 
>> ost->enc->supported_framerates);
>>               ost->frame_rate = ost->enc->supported_framerates[idx];
>> diff --git a/fftools/ffmpeg.h b/fftools/ffmpeg.h
>> index 8046e75026..3662130da4 100644
>> --- a/fftools/ffmpeg.h
>> +++ b/fftools/ffmpeg.h
>> @@ -108,6 +108,8 @@ typedef struct OptionsContext {
>>       int        nb_audio_sample_rate;
>>       SpecifierOpt *frame_rates;
>>       int        nb_frame_rates;
>> +    SpecifierOpt *max_frame_rates;
>> +    int        nb_max_frame_rates;
>>       SpecifierOpt *frame_sizes;
>>       int        nb_frame_sizes;
>>       SpecifierOpt *frame_pix_fmts;
>> @@ -479,6 +481,7 @@ typedef struct OutputStream {
>>       /* video only */
>>       AVRational frame_rate;
>> +    AVRational max_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 bf2eb26246..2080499e65 100644
>> --- a/fftools/ffmpeg_opt.c
>> +++ b/fftools/ffmpeg_opt.c
>> @@ -55,6 +55,7 @@ static const char *const 
>> opt_name_codec_names[]               = {"c", "codec", "
>>   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[]           = 
>> {"rmax", 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};
>> @@ -1688,7 +1689,7 @@ static OutputStream 
>> *new_video_stream(OptionsContext *o, AVFormatContext *oc, in
>>       AVStream *st;
>>       OutputStream *ost;
>>       AVCodecContext *video_enc;
>> -    char *frame_rate = NULL, *frame_aspect_ratio = NULL;
>> +    char *frame_rate = NULL, *max_frame_rate = NULL, 
>> *frame_aspect_ratio = NULL;
>>       ost = new_output_stream(o, oc, AVMEDIA_TYPE_VIDEO, source_index);
>>       st  = ost->st;
>> @@ -1699,8 +1700,22 @@ static OutputStream 
>> *new_video_stream(OptionsContext *o, AVFormatContext *oc, in
>>           av_log(NULL, AV_LOG_FATAL, "Invalid framerate value: %s\n", 
>> frame_rate);
>>           exit_program(1);
>>       }
>> -    if (frame_rate && video_sync_method == VSYNC_PASSTHROUGH)
>> -        av_log(NULL, AV_LOG_ERROR, "Using -vsync 0 and -r can produce 
>> invalid output files\n");
>> +
>> +    MATCH_PER_STREAM_OPT(max_frame_rates, str, max_frame_rate, oc, st);
>> +    if (max_frame_rate && av_parse_video_rate(&ost->max_frame_rate, 
>> max_frame_rate) < 0) {
>> +        av_log(NULL, AV_LOG_FATAL, "Invalid maximum framerate value: 
>> %s\n", max_frame_rate);
>> +        exit_program(1);
>> +    }
>> +
>> +    if (frame_rate && max_frame_rate) {
>> +        av_log(NULL, AV_LOG_WARNING, "-rmax for stream %d:%d will 
>> have no effect as"
>> +               " -r is also set.\n", ost->file_index, ost->index);
>> +        ost->max_frame_rate = (AVRational){0, 1};
>> +    }
>> +
>> +    if ((frame_rate || max_frame_rate) &&
>> +        video_sync_method == VSYNC_PASSTHROUGH)
>> +        av_log(NULL, AV_LOG_ERROR, "Using -vsync 0 and -r/-rmax can 
>> produce invalid output files\n");
>>       MATCH_PER_STREAM_OPT(frame_aspect_ratios, str, 
>> frame_aspect_ratio, oc, st);
>>       if (frame_aspect_ratio) {
>> @@ -3596,6 +3611,9 @@ const OptionDef options[] = {
>>       { "r",            OPT_VIDEO | HAS_ARG  | OPT_STRING | OPT_SPEC |
>>                         OPT_INPUT | 
>> OPT_OUTPUT,                                    { .off = 
>> OFFSET(frame_rates) },
>>           "set frame rate (Hz value, fraction or abbreviation)", 
>> "rate" },
>> +    { "rmax",         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" },
>>       { "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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