doc: clarify -frames options behavior

Replace "frames to record" with "frames to output". The "to record"
makes it seem like an input option, or that it would capture the frames
instead of outputting them.
Reviewed-by: Timothy Gu <timothygu99@gmail.com>
Signed-off-by: Lou Logan <lou@lrcd.com>

doc/ffmpeg.texi

@@ -360,7 +360,7 @@ ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
 @end example
 
 @item -dframes @var{number} (@emph{output})
-Set the number of data frames to record. This is an alias for @code{-frames:d}.
+Set the number of data frames to output. This is an alias for @code{-frames:d}.
 
 @item -frames[:@var{stream_specifier}] @var{framecount} (@emph{output,per-stream})
 Stop writing to the stream after @var{framecount} frames.
@@ -467,7 +467,7 @@ attachments.
 
 @table @option
 @item -vframes @var{number} (@emph{output})
-Set the number of video frames to record. This is an alias for @code{-frames:v}.
+Set the number of video frames to output. This is an alias for @code{-frames:v}.
 @item -r[:@var{stream_specifier}] @var{fps} (@emph{input/output,per-stream})
 Set frame rate (Hz value, fraction or abbreviation).
 
@@ -692,7 +692,7 @@ If this option is not specified, the default adapter is used.
 
 @table @option
 @item -aframes @var{number} (@emph{output})
-Set the number of audio frames to record. This is an alias for @code{-frames:a}.
+Set the number of audio frames to output. This is an alias for @code{-frames:a}.
 @item -ar[:@var{stream_specifier}] @var{freq} (@emph{input/output,per-stream})
 Set the audio sampling frequency. For output streams it is set by
 default to the frequency of the corresponding input stream. For input

ffmpeg_opt.c

@@ -2815,7 +2815,7 @@ const OptionDef options[] = {
         "add metadata", "string=string" },
     { "dframes",        HAS_ARG | OPT_PERFILE | OPT_EXPERT |
                         OPT_OUTPUT,                                  { .func_arg = opt_data_frames },
-        "set the number of data frames to record", "number" },
+        "set the number of data frames to output", "number" },
     { "benchmark",      OPT_BOOL | OPT_EXPERT,                       { &do_benchmark },
         "add timings for benchmarking" },
     { "benchmark_all",  OPT_BOOL | OPT_EXPERT,                       { &do_benchmark_all },
@@ -2866,7 +2866,7 @@ const OptionDef options[] = {
     { "copypriorss",    OPT_INT | HAS_ARG | OPT_EXPERT | OPT_SPEC | OPT_OUTPUT,   { .off = OFFSET(copy_prior_start) },
         "copy or discard frames before start time" },
     { "frames",         OPT_INT64 | HAS_ARG | OPT_SPEC | OPT_OUTPUT, { .off = OFFSET(max_frames) },
-        "set the number of frames to record", "number" },
+        "set the number of frames to output", "number" },
     { "tag",            OPT_STRING | HAS_ARG | OPT_SPEC |
                         OPT_EXPERT | OPT_OUTPUT | OPT_INPUT,         { .off = OFFSET(codec_tags) },
         "force codec tag/fourcc", "fourcc/tag" },
@@ -2908,7 +2908,7 @@ const OptionDef options[] = {
 
     /* video options */
     { "vframes",      OPT_VIDEO | HAS_ARG  | OPT_PERFILE | OPT_OUTPUT,           { .func_arg = opt_video_frames },
-        "set the number of video frames to record", "number" },
+        "set the number of video frames to output", "number" },
     { "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" },
@@ -2996,7 +2996,7 @@ const OptionDef options[] = {
 
     /* audio options */
     { "aframes",        OPT_AUDIO | HAS_ARG  | OPT_PERFILE | OPT_OUTPUT,           { .func_arg = opt_audio_frames },
-        "set the number of audio frames to record", "number" },
+        "set the number of audio frames to output", "number" },
     { "aq",             OPT_AUDIO | HAS_ARG  | OPT_PERFILE | OPT_OUTPUT,           { .func_arg = opt_audio_qscale },
         "set audio quality (codec-specific)", "quality", },
     { "ar",             OPT_AUDIO | HAS_ARG  | OPT_INT | OPT_SPEC |