fftools/ffmpeg_enc: only use fallback framerate when encoding CFR

When no output video framerate is specified by the user with -r or can
be inferred from the filtergraph, encoder setup will arbitrarily decide
that the framerate is 25fps. However, making up any framerate value for
VFR encoding is at best unnecessary.

Changes the results of the sub2video tests, where the input timebase is
now used instead of 1/25.

3 files changed, 112 insertions, 107 deletions

diff --git a/fftools/ffmpeg_enc.c b/fftools/ffmpeg_enc.c
index 4b5bd3d9b4..80a49fe606 100644
--- a/fftools/ffmpeg_enc.c
+++ b/fftools/ffmpeg_enc.c
@@ -231,20 +231,24 @@ static int enc_choose_timebase(OutputStream *ost, AVFrame *frame)
     fr = ost->frame_rate;
     if (!fr.num)
         fr = fd->frame_rate_filter;
-    if (!fr.num && !ost->max_frame_rate.num) {
-        fr = (AVRational){25, 1};
-        av_log(ost, AV_LOG_WARNING,
-               "No information "
-               "about the input framerate is available. Falling "
-               "back to a default value of 25fps. Use the -r option "
-               "if you want a different framerate.\n");
-    }
 
-    if (ost->max_frame_rate.num &&
-        (av_q2d(fr) > av_q2d(ost->max_frame_rate) ||
-        !fr.den))
-        fr = ost->max_frame_rate;
+    if (ost->is_cfr) {
+        if (!fr.num && !ost->max_frame_rate.num) {
+            fr = (AVRational){25, 1};
+            av_log(ost, AV_LOG_WARNING,
+                   "No information "
+                   "about the input framerate is available. Falling "
+                   "back to a default value of 25fps. Use the -r option "
+                   "if you want a different framerate.\n");
+        }
+
+        if (ost->max_frame_rate.num &&
+            (av_q2d(fr) > av_q2d(ost->max_frame_rate) ||
+            !fr.den))
+            fr = ost->max_frame_rate;
+    }
 
+    if (fr.num > 0) {
     if (enc->codec->supported_framerates && !ost->force_fps) {
         int idx = av_find_nearest_q_idx(fr, enc->codec->supported_framerates);
         fr = enc->codec->supported_framerates[idx];
@@ -254,6 +258,7 @@ static int enc_choose_timebase(OutputStream *ost, AVFrame *frame)
         av_reduce(&fr.num, &fr.den,
                   fr.num, fr.den, 65535);
     }
+    }
 
     if (av_q2d(fr) > 1e3 && ost->vsync_method != VSYNC_PASSTHROUGH &&
         (ost->vsync_method == VSYNC_CFR || ost->vsync_method == VSYNC_VSCFR ||
diff --git a/tests/ref/fate/sub2video_basic b/tests/ref/fate/sub2video_basic
index 5f72e292c9..a6eb1a34ea 100644
--- a/tests/ref/fate/sub2video_basic
+++ b/tests/ref/fate/sub2video_basic
@@ -1,95 +1,95 @@
-#tb 0: 1/25
+#tb 0: 1/1000
 #media_type 0: video
 #codec_id 0: rawvideo
 #dimensions 0: 720x480
 #sar 0: 0/1
-0,       3312,       3312,        1,  1382400, 0x00000000
-0,       3312,       3312,        1,  1382400, 0x8c93c2ba
-0,       3436,       3436,        1,  1382400, 0x00000000
-0,       3684,       3684,        1,  1382400, 0xb02e32ca
-0,       3802,       3802,        1,  1382400, 0x00000000
-0,       4520,       4520,        1,  1382400, 0x83b71116
-0,       4584,       4584,        1,  1382400, 0x00000000
-0,       4586,       4586,        1,  1382400, 0x85547fd1
-0,       4645,       4645,        1,  1382400, 0x00000000
-0,       4648,       4648,        1,  1382400, 0x00000000
-0,       4648,       4648,        1,  1382400, 0xb6a8f181
-0,       4715,       4715,        1,  1382400, 0x00000000
-0,       4717,       4717,        1,  1382400, 0xb64d1a2c
-0,       4748,       4748,        1,  1382400, 0x00000000
-0,       4750,       4750,        1,  1382400, 0x7b37ecf3
-0,       4792,       4792,        1,  1382400, 0x00000000
-0,       4993,       4993,        1,  1382400, 0xdc025bd1
-0,       5027,       5027,        1,  1382400, 0x00000000
-0,       5029,       5029,        1,  1382400, 0x688b294d
-0,       5068,       5068,        1,  1382400, 0x00000000
-0,       5070,       5070,        1,  1382400, 0xa2b33d1b
-0,       5117,       5117,        1,  1382400, 0x00000000
-0,       5119,       5119,        1,  1382400, 0xb3e525e3
-0,       5168,       5168,        1,  1382400, 0x00000000
-0,       5170,       5170,        1,  1382400, 0xaa8fbdd7
-0,       5216,       5216,        1,  1382400, 0x00000000
-0,       5218,       5218,        1,  1382400, 0x7b7f26dd
-0,       5249,       5249,        1,  1382400, 0x00000000
-0,       5251,       5251,        1,  1382400, 0x15e2f836
-0,       5289,       5289,        1,  1382400, 0x00000000
-0,       5291,       5291,        1,  1382400, 0x0fee9b0c
-0,       5358,       5358,        1,  1382400, 0x00000000
-0,       5360,       5360,        1,  1382400, 0x89d62791
-0,       5429,       5429,        1,  1382400, 0x00000000
-0,       5431,       5431,        1,  1382400, 0xa6a9fd74
-0,       5490,       5490,        1,  1382400, 0x00000000
-0,       5491,       5491,        1,  1382400, 0x7896178d
-0,       5537,       5537,        1,  1382400, 0x00000000
-0,       5588,       5588,        1,  1382400, 0x01751a52
-0,       5647,       5647,        1,  1382400, 0x00000000
-0,       5688,       5688,        1,  1382400, 0xa3959c6f
-0,       5770,       5770,        1,  1382400, 0x00000000
-0,       5772,       5772,        1,  1382400, 0x3d3ea47b
-0,       5826,       5826,        1,  1382400, 0x00000000
-0,       5828,       5828,        1,  1382400, 0x593f8b24
-0,       5931,       5931,        1,  1382400, 0x00000000
-0,       5933,       5933,        1,  1382400, 0x171f05ba
-0,       6001,       6001,        1,  1382400, 0x00000000
-0,       6003,       6003,        1,  1382400, 0xb014cdf1
-0,       6054,       6054,        1,  1382400, 0x00000000
-0,       6839,       6839,        1,  1382400, 0xd918e667
-0,       6880,       6880,        1,  1382400, 0x00000000
-0,       7386,       7386,        1,  1382400, 0xc9406331
-0,       7419,       7419,        1,  1382400, 0x00000000
-0,       7501,       7501,        1,  1382400, 0xaf08b10d
-0,       7549,       7549,        1,  1382400, 0x00000000
-0,       7551,       7551,        1,  1382400, 0x00000000
-0,       7551,       7551,        1,  1382400, 0x853a9d93
-0,       7589,       7589,        1,  1382400, 0x00000000
-0,       7605,       7605,        1,  1382400, 0x7491a87d
-0,       7647,       7647,        1,  1382400, 0x00000000
-0,       7649,       7649,        1,  1382400, 0xf7383c58
-0,       7697,       7697,        1,  1382400, 0x00000000
-0,       7699,       7699,        1,  1382400, 0xe66be411
-0,       7743,       7743,        1,  1382400, 0x00000000
-0,       8032,       8032,        1,  1382400, 0xd6850362
-0,       8082,       8082,        1,  1382400, 0x00000000
-0,       8084,       8084,        1,  1382400, 0x3e1ed109
-0,       8115,       8115,        1,  1382400, 0x00000000
-0,       8116,       8116,        1,  1382400, 0x39c1b7bd
-0,       8160,       8160,        1,  1382400, 0x00000000
-0,       8180,       8180,        1,  1382400, 0x35b85f2e
-0,       8207,       8207,        1,  1382400, 0x00000000
-0,       8209,       8209,        1,  1382400, 0x00000000
-0,       8209,       8209,        1,  1382400, 0x83f103e5
-0,       8247,       8247,        1,  1382400, 0x00000000
-0,       8249,       8249,        1,  1382400, 0xbc1ca9b3
-0,       8278,       8278,        1,  1382400, 0x00000000
-0,       8281,       8281,        1,  1382400, 0x94d4a51e
-0,       8321,       8321,        1,  1382400, 0x00000000
-0,       8323,       8323,        1,  1382400, 0xf88cdfde
-0,       8367,       8367,        1,  1382400, 0x00000000
-0,       8565,       8565,        1,  1382400, 0xdd51423b
-0,       8611,       8611,        1,  1382400, 0x00000000
-0,       8669,       8669,        1,  1382400, 0x08259fa4
-0,       8708,       8708,        1,  1382400, 0x00000000
-0,       8941,       8941,        1,  1382400, 0x1663fa34
-0,       8994,       8994,        1,  1382400, 0x00000000
-0,       8996,       8996,        1,  1382400, 0xda2ceb55
-0,       9027,       9027,        1,  1382400, 0x00000000
+0,     132499,     132499,        0,  1382400, 0x00000000
+0,     132499,     132499,        0,  1382400, 0x8c93c2ba
+0,     137459,     137459,        0,  1382400, 0x00000000
+0,     147355,     147355,        0,  1382400, 0xb02e32ca
+0,     152088,     152088,        0,  1382400, 0x00000000
+0,     180797,     180797,        0,  1382400, 0x83b71116
+0,     183357,     183357,        0,  1382400, 0x00000000
+0,     183433,     183433,        0,  1382400, 0x85547fd1
+0,     185799,     185799,        0,  1382400, 0x00000000
+0,     185909,     185909,        0,  1382400, 0x00000000
+0,     185910,     185910,        0,  1382400, 0xb6a8f181
+0,     188606,     188606,        0,  1382400, 0x00000000
+0,     188663,     188663,        0,  1382400, 0xb64d1a2c
+0,     189925,     189925,        0,  1382400, 0x00000000
+0,     190014,     190014,        0,  1382400, 0x7b37ecf3
+0,     191675,     191675,        0,  1382400, 0x00000000
+0,     199724,     199724,        0,  1382400, 0xdc025bd1
+0,     201089,     201089,        0,  1382400, 0x00000000
+0,     201175,     201175,        0,  1382400, 0x688b294d
+0,     202733,     202733,        0,  1382400, 0x00000000
+0,     202819,     202819,        0,  1382400, 0xa2b33d1b
+0,     204684,     204684,        0,  1382400, 0x00000000
+0,     204762,     204762,        0,  1382400, 0xb3e525e3
+0,     206730,     206730,        0,  1382400, 0x00000000
+0,     206806,     206806,        0,  1382400, 0xaa8fbdd7
+0,     208637,     208637,        0,  1382400, 0x00000000
+0,     208716,     208716,        0,  1382400, 0x7b7f26dd
+0,     209978,     209978,        0,  1382400, 0x00000000
+0,     210051,     210051,        0,  1382400, 0x15e2f836
+0,     211575,     211575,        0,  1382400, 0x00000000
+0,     211644,     211644,        0,  1382400, 0x0fee9b0c
+0,     214306,     214306,        0,  1382400, 0x00000000
+0,     214380,     214380,        0,  1382400, 0x89d62791
+0,     217144,     217144,        0,  1382400, 0x00000000
+0,     217225,     217225,        0,  1382400, 0xa6a9fd74
+0,     219591,     219591,        0,  1382400, 0x00000000
+0,     219652,     219652,        0,  1382400, 0x7896178d
+0,     221483,     221483,        0,  1382400, 0x00000000
+0,     223531,     223531,        0,  1382400, 0x01751a52
+0,     225863,     225863,        0,  1382400, 0x00000000
+0,     227510,     227510,        0,  1382400, 0xa3959c6f
+0,     230809,     230809,        0,  1382400, 0x00000000
+0,     230872,     230872,        0,  1382400, 0x3d3ea47b
+0,     233033,     233033,        0,  1382400, 0x00000000
+0,     233124,     233124,        0,  1382400, 0x593f8b24
+0,     237220,     237220,        0,  1382400, 0x00000000
+0,     237303,     237303,        0,  1382400, 0x171f05ba
+0,     240033,     240033,        0,  1382400, 0x00000000
+0,     240106,     240106,        0,  1382400, 0xb014cdf1
+0,     242165,     242165,        0,  1382400, 0x00000000
+0,     273556,     273556,        0,  1382400, 0xd918e667
+0,     275217,     275217,        0,  1382400, 0x00000000
+0,     295445,     295445,        0,  1382400, 0xc9406331
+0,     296776,     296776,        0,  1382400, 0x00000000
+0,     300049,     300049,        0,  1382400, 0xaf08b10d
+0,     301949,     301949,        0,  1382400, 0x00000000
+0,     302034,     302034,        0,  1382400, 0x00000000
+0,     302035,     302035,        0,  1382400, 0x853a9d93
+0,     303559,     303559,        0,  1382400, 0x00000000
+0,     304203,     304203,        0,  1382400, 0x7491a87d
+0,     305898,     305898,        0,  1382400, 0x00000000
+0,     305947,     305947,        0,  1382400, 0xf7383c58
+0,     307881,     307881,        0,  1382400, 0x00000000
+0,     307957,     307957,        0,  1382400, 0xe66be411
+0,     309720,     309720,        0,  1382400, 0x00000000
+0,     321295,     321295,        0,  1382400, 0xd6850362
+0,     323263,     323263,        0,  1382400, 0x00000000
+0,     323356,     323356,        0,  1382400, 0x3e1ed109
+0,     324584,     324584,        0,  1382400, 0x00000000
+0,     324640,     324640,        0,  1382400, 0x39c1b7bd
+0,     326403,     326403,        0,  1382400, 0x00000000
+0,     327193,     327193,        0,  1382400, 0x35b85f2e
+0,     328285,     328285,        0,  1382400, 0x00000000
+0,     328360,     328360,        0,  1382400, 0x00000000
+0,     328361,     328361,        0,  1382400, 0x83f103e5
+0,     329885,     329885,        0,  1382400, 0x00000000
+0,     329946,     329946,        0,  1382400, 0xbc1ca9b3
+0,     331106,     331106,        0,  1382400, 0x00000000
+0,     331230,     331230,        0,  1382400, 0x94d4a51e
+0,     332857,     332857,        0,  1382400, 0x00000000
+0,     332924,     332924,        0,  1382400, 0xf88cdfde
+0,     334687,     334687,        0,  1382400, 0x00000000
+0,     342600,     342600,        0,  1382400, 0xdd51423b
+0,     344431,     344431,        0,  1382400, 0x00000000
+0,     346771,     346771,        0,  1382400, 0x08259fa4
+0,     348329,     348329,        0,  1382400, 0x00000000
+0,     357640,     357640,        0,  1382400, 0x1663fa34
+0,     359767,     359767,        0,  1382400, 0x00000000
+0,     359834,     359834,        0,  1382400, 0xda2ceb55
+0,     361096,     361096,        0,  1382400, 0x00000000
diff --git a/tests/ref/fate/sub2video_time_limited b/tests/ref/fate/sub2video_time_limited
index 9fb6fb06f9..c7d48d639f 100644
--- a/tests/ref/fate/sub2video_time_limited
+++ b/tests/ref/fate/sub2video_time_limited
@@ -1,8 +1,8 @@
-#tb 0: 1/25
+#tb 0: 1/90000
 #media_type 0: video
 #codec_id 0: rawvideo
 #dimensions 0: 1920x1080
 #sar 0: 0/1
-0,          2,          2,        1,  8294400, 0x00000000
-0,          2,          2,        1,  8294400, 0xa87c518f
-0,         10,         10,        1,  8294400, 0xa87c518f
+0,       6072,       6072,        0,  8294400, 0x00000000
+0,       6072,       6072,        0,  8294400, 0xa87c518f
+0,      36101,      36101,        0,  8294400, 0xa87c518f