[FFmpeg-devel] [PATCH v2] ffmpeg: add option fps_mode

[Gyan Doshi <ffmpeg@gyani.pro>]

fps_mode sets video sync per output stream. Overrides vsync for matching
streams.

vsync is deprecated.
---
 doc/ffmpeg.texi      | 14 ++++++++------
 fftools/ffmpeg.c     |  9 +++++----
 fftools/ffmpeg.h     |  3 +++
 fftools/ffmpeg_mux.c |  2 +-
 fftools/ffmpeg_opt.c | 42 +++++++++++++++++++++++++++++++-----------
 5 files changed, 48 insertions(+), 22 deletions(-)

diff --git a/doc/ffmpeg.texi b/doc/ffmpeg.texi
index 0d7e1a479d..51515c2cb8 100644
--- a/doc/ffmpeg.texi
+++ b/doc/ffmpeg.texi
@@ -1618,12 +1618,14 @@ it may cause packet loss.
 It is useful for when flow speed of output packets is important, such as live streaming.
 @item -re (@emph{input})
 Read input at native frame rate. This is equivalent to setting @code{-readrate 1}.
-@item -vsync @var{parameter}
-Video sync method.
-
-For compatibility reasons some of the values can be specified as numbers (shown
-in parentheses in the following table). This is deprecated and will stop working
-in the future.
+@item -vsync @var{parameter} (@emph{global})
+@itemx -fps_mode[:@var{stream_specifier}] @var{parameter} (@emph{output,per-stream})
+Set video sync method / framerate mode. vsync is applied to all output video streams
+but can be overridden for a stream by setting fps_mode. vsync is deprecated and will be
+removed in the future.
+
+For compatibility reasons some of the values for vsync can be specified as numbers (shown
+in parentheses in the following table).
 
 @table @option
 @item passthrough (0)
diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
index a5e1bf3993..09caa3e3c4 100644
--- a/fftools/ffmpeg.c
+++ b/fftools/ffmpeg.c
@@ -3017,11 +3017,12 @@ static int init_output_stream_encode(OutputStream *ost, AVFrame *frame)
 
         if (!(enc_ctx->time_base.num && enc_ctx->time_base.den))
             enc_ctx->time_base = av_buffersink_get_time_base(ost->filter->filter);
-        if (   av_q2d(enc_ctx->time_base) < 0.001 && video_sync_method != VSYNC_PASSTHROUGH
-           && (video_sync_method == VSYNC_CFR || video_sync_method == VSYNC_VSCFR ||
-               (video_sync_method == VSYNC_AUTO && !(of->format->flags & AVFMT_VARIABLE_FPS)))){
+        if (   av_q2d(enc_ctx->time_base) < 0.001 && ost->vsync_method != VSYNC_PASSTHROUGH
+           && (ost->vsync_method == VSYNC_CFR || ost->vsync_method == VSYNC_VSCFR ||
+               (ost->vsync_method == VSYNC_AUTO && !(of->format->flags & AVFMT_VARIABLE_FPS)))){
             av_log(oc, AV_LOG_WARNING, "Frame rate very high for a muxer not efficiently supporting it.\n"
-                                       "Please consider specifying a lower framerate, a different muxer or -vsync 2\n");
+                                       "Please consider specifying a lower framerate, a different muxer or "
+                                       "setting vsync/fps_mode to vfr\n");
         }
 
         enc_ctx->width  = av_buffersink_get_w(ost->filter->filter);
diff --git a/fftools/ffmpeg.h b/fftools/ffmpeg.h
index 7326193caf..69a368b8d1 100644
--- a/fftools/ffmpeg.h
+++ b/fftools/ffmpeg.h
@@ -176,6 +176,8 @@ typedef struct OptionsContext {
     int        nb_qscale;
     SpecifierOpt *forced_key_frames;
     int        nb_forced_key_frames;
+    SpecifierOpt *fps_mode;
+    int        nb_fps_mode;
     SpecifierOpt *force_fps;
     int        nb_force_fps;
     SpecifierOpt *frame_aspect_ratios;
@@ -489,6 +491,7 @@ typedef struct OutputStream {
     AVRational max_frame_rate;
     enum VideoSyncMethod vsync_method;
     int is_cfr;
+    const char *fps_mode;
     int force_fps;
     int top_field_first;
     int rotate_overridden;
diff --git a/fftools/ffmpeg_mux.c b/fftools/ffmpeg_mux.c
index 794d580635..a55fd18f8f 100644
--- a/fftools/ffmpeg_mux.c
+++ b/fftools/ffmpeg_mux.c
@@ -96,7 +96,7 @@ void of_write_packet(OutputFile *of, AVPacket *pkt, OutputStream *ost,
         return;
     }
 
-    if ((st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO && video_sync_method == VSYNC_DROP) ||
+    if ((st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO && ost->vsync_method == VSYNC_DROP) ||
         (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO && audio_sync_method < 0))
         pkt->pts = pkt->dts = AV_NOPTS_VALUE;
 
diff --git a/fftools/ffmpeg_opt.c b/fftools/ffmpeg_opt.c
index 2c1b3bd0dd..398067da96 100644
--- a/fftools/ffmpeg_opt.c
+++ b/fftools/ffmpeg_opt.c
@@ -81,6 +81,7 @@ static const char *const opt_name_codec_tags[]                = {"tag", "atag",
 static const char *const opt_name_sample_fmts[]               = {"sample_fmt", NULL};
 static const char *const opt_name_qscale[]                    = {"q", "qscale", NULL};
 static const char *const opt_name_forced_key_frames[]         = {"forced_key_frames", NULL};
+static const char *const opt_name_fps_mode[]                  = {"fps_mode", NULL};
 static const char *const opt_name_force_fps[]                 = {"force_fps", NULL};
 static const char *const opt_name_frame_aspect_ratios[]       = {"aspect", NULL};
 static const char *const opt_name_rc_overrides[]              = {"rc_override", NULL};
@@ -265,6 +266,26 @@ static AVDictionary *strip_specifiers(AVDictionary *dict)
     return ret;
 }
 
+static int parse_and_set_vsync(const char *arg, int *vsync_var, int file_idx, int st_idx, int is_global)
+{
+    if      (!av_strcasecmp(arg, "cfr"))         *vsync_var = VSYNC_CFR;
+    else if (!av_strcasecmp(arg, "vfr"))         *vsync_var = VSYNC_VFR;
+    else if (!av_strcasecmp(arg, "passthrough")) *vsync_var = VSYNC_PASSTHROUGH;
+    else if (!av_strcasecmp(arg, "drop"))        *vsync_var = VSYNC_DROP;
+    else if (!is_global && !av_strcasecmp(arg, "auto"))  *vsync_var = VSYNC_AUTO;
+    else if (!is_global) {
+        av_log(NULL, AV_LOG_FATAL, "Invalid value %s specified for fps_mode of #%d:%d.\n", arg, file_idx, st_idx);
+        exit_program(1);
+    }
+
+    if (is_global && *vsync_var == VSYNC_AUTO) {
+        video_sync_method = parse_number_or_die("vsync", arg, OPT_INT, VSYNC_AUTO, VSYNC_VFR);
+        av_log(NULL, AV_LOG_WARNING, "Passing a number to -vsync is deprecated,"
+               " use a string argument as described in the manual.\n");
+    }
+    return 0;
+}
+
 static int opt_filter_threads(void *optctx, const char *opt, const char *arg)
 {
     av_free(filter_nbthreads);
@@ -1905,6 +1926,10 @@ static OutputStream *new_video_stream(OptionsContext *o, AVFormatContext *oc, in
         MATCH_PER_STREAM_OPT(top_field_first, i, ost->top_field_first, oc, st);
 
         ost->vsync_method = video_sync_method;
+        MATCH_PER_STREAM_OPT(fps_mode, str, ost->fps_mode, oc, st);
+        if (ost->fps_mode)
+            parse_and_set_vsync(ost->fps_mode, &ost->vsync_method, ost->file_index, ost->index, 0);
+
         if (ost->vsync_method == VSYNC_AUTO) {
             if (!strcmp(oc->oformat->name, "avi")) {
                 ost->vsync_method = VSYNC_VFR;
@@ -3248,16 +3273,8 @@ static int opt_audio_filters(void *optctx, const char *opt, const char *arg)
 
 static int opt_vsync(void *optctx, const char *opt, const char *arg)
 {
-    if      (!av_strcasecmp(arg, "cfr"))         video_sync_method = VSYNC_CFR;
-    else if (!av_strcasecmp(arg, "vfr"))         video_sync_method = VSYNC_VFR;
-    else if (!av_strcasecmp(arg, "passthrough")) video_sync_method = VSYNC_PASSTHROUGH;
-    else if (!av_strcasecmp(arg, "drop"))        video_sync_method = VSYNC_DROP;
-
-    if (video_sync_method == VSYNC_AUTO) {
-        video_sync_method = parse_number_or_die("vsync", arg, OPT_INT, VSYNC_AUTO, VSYNC_VFR);
-        av_log(NULL, AV_LOG_WARNING, "Passing a number to -vsync is deprecated,"
-               " use a string argument as described in the manual.\n");
-    }
+    av_log(NULL, AV_LOG_WARNING, "-vsync is deprecated. Use -fps_mode\n");
+    parse_and_set_vsync(arg, &video_sync_method, -1, -1, 1);
     return 0;
 }
 
@@ -3620,7 +3637,7 @@ const OptionDef options[] = {
         "specify target file type (\"vcd\", \"svcd\", \"dvd\", \"dv\" or \"dv50\" "
         "with optional prefixes \"pal-\", \"ntsc-\" or \"film-\")", "type" },
     { "vsync",          HAS_ARG | OPT_EXPERT,                        { .func_arg = opt_vsync },
-        "video sync method", "" },
+        "set video sync method globally; deprecated, use -fps_mode", "" },
     { "frame_drop_threshold", HAS_ARG | OPT_FLOAT | OPT_EXPERT,      { &frame_drop_threshold },
         "frame drop threshold", "" },
     { "async",          HAS_ARG | OPT_INT | OPT_EXPERT,              { &audio_sync_method },
@@ -3777,6 +3794,9 @@ const OptionDef options[] = {
         "force video tag/fourcc", "fourcc/tag" },
     { "qphist",       OPT_VIDEO | OPT_BOOL | OPT_EXPERT ,                        { &qp_hist },
         "show QP histogram" },
+    { "fps_mode",     OPT_VIDEO | HAS_ARG | OPT_STRING | OPT_EXPERT |
+                      OPT_SPEC | OPT_OUTPUT,                                     { .off = OFFSET(fps_mode) },
+        "set framerate mode for matching video streams; overrides vsync" },
     { "force_fps",    OPT_VIDEO | OPT_BOOL | OPT_EXPERT  | OPT_SPEC |
                       OPT_OUTPUT,                                                { .off = OFFSET(force_fps) },
         "force the selected framerate, disable the best supported framerate selection" },
-- 
2.36.1

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