lavf: add avformat_transfer_internal_stream_timing_info() and use it in ffmpeg

In lavf we have access to st->internal->avctx so it's a better place
than in ffmpeg*.c and will allow moving to codecpar.

3 files changed, 89 insertions, 2 deletions

diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index 43b225bb5a..21e505d2ae 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -2895,6 +2895,29 @@ int av_apply_bitstream_filters(AVCodecContext *codec, AVPacket *pkt,
                                AVBitStreamFilterContext *bsfc);
 #endif
 
+enum AVTimebaseSource {
+    AVFMT_TBCF_AUTO = -1,
+    AVFMT_TBCF_DECODER,
+    AVFMT_TBCF_DEMUXER,
+#if FF_API_R_FRAME_RATE
+    AVFMT_TBCF_R_FRAMERATE,
+#endif
+};
+
+/**
+ * Transfer internal timing information from one stream to another.
+ *
+ * This function is useful when doing stream copy.
+ *
+ * @param ofmt     target output format for ost
+ * @param ost      output stream which needs timings copy and adjustments
+ * @param ist      reference input stream to copy timings from
+ * @param copy_tb  define from where the stream codec timebase needs to be imported
+ */
+int avformat_transfer_internal_stream_timing_info(const AVOutputFormat *ofmt,
+                                                  AVStream *ost, const AVStream *ist,
+                                                  enum AVTimebaseSource copy_tb);
+
 /**
  * @}
  */
diff --git a/libavformat/utils.c b/libavformat/utils.c
index 76cbff4ef6..f4a836d80d 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -5281,3 +5281,67 @@ int ff_bprint_to_codecpar_extradata(AVCodecParameters *par, struct AVBPrint *buf
     par->extradata_size = buf->len;
     return 0;
 }
+
+int avformat_transfer_internal_stream_timing_info(const AVOutputFormat *ofmt,
+                                                  AVStream *ost, const AVStream *ist,
+                                                  enum AVTimebaseSource copy_tb)
+{
+    //TODO: use [io]st->internal->avctx
+    const AVCodecContext *dec_ctx = ist->codec;
+    AVCodecContext       *enc_ctx = ost->codec;
+
+    enc_ctx->time_base = ist->time_base;
+    /*
+     * Avi is a special case here because it supports variable fps but
+     * having the fps and timebase differe significantly adds quite some
+     * overhead
+     */
+    if (!strcmp(ofmt->name, "avi")) {
+#if FF_API_R_FRAME_RATE
+        if (copy_tb == AVFMT_TBCF_AUTO && ist->r_frame_rate.num
+            && av_q2d(ist->r_frame_rate) >= av_q2d(ist->avg_frame_rate)
+            && 0.5/av_q2d(ist->r_frame_rate) > av_q2d(ist->time_base)
+            && 0.5/av_q2d(ist->r_frame_rate) > av_q2d(dec_ctx->time_base)
+            && av_q2d(ist->time_base) < 1.0/500 && av_q2d(dec_ctx->time_base) < 1.0/500
+            || copy_tb == AVFMT_TBCF_R_FRAMERATE) {
+            enc_ctx->time_base.num = ist->r_frame_rate.den;
+            enc_ctx->time_base.den = 2*ist->r_frame_rate.num;
+            enc_ctx->ticks_per_frame = 2;
+        } else
+#endif
+            if (copy_tb == AVFMT_TBCF_AUTO && av_q2d(dec_ctx->time_base)*dec_ctx->ticks_per_frame > 2*av_q2d(ist->time_base)
+                   && av_q2d(ist->time_base) < 1.0/500
+                   || copy_tb == AVFMT_TBCF_DECODER) {
+            enc_ctx->time_base = dec_ctx->time_base;
+            enc_ctx->time_base.num *= dec_ctx->ticks_per_frame;
+            enc_ctx->time_base.den *= 2;
+            enc_ctx->ticks_per_frame = 2;
+        }
+    } else if (!(ofmt->flags & AVFMT_VARIABLE_FPS)
+               && strcmp(ofmt->name, "mov") && strcmp(ofmt->name, "mp4") && strcmp(ofmt->name, "3gp")
+               && strcmp(ofmt->name, "3g2") && strcmp(ofmt->name, "psp") && strcmp(ofmt->name, "ipod")
+               && strcmp(ofmt->name, "f4v")) {
+        if (copy_tb == AVFMT_TBCF_AUTO && dec_ctx->time_base.den
+            && av_q2d(dec_ctx->time_base)*dec_ctx->ticks_per_frame > av_q2d(ist->time_base)
+            && av_q2d(ist->time_base) < 1.0/500
+            || copy_tb == AVFMT_TBCF_DECODER) {
+            enc_ctx->time_base = dec_ctx->time_base;
+            enc_ctx->time_base.num *= dec_ctx->ticks_per_frame;
+        }
+    }
+
+    if (enc_ctx->codec_tag == AV_RL32("tmcd")
+        && dec_ctx->time_base.num < dec_ctx->time_base.den
+        && dec_ctx->time_base.num > 0
+        && 121LL*dec_ctx->time_base.num > dec_ctx->time_base.den) {
+        enc_ctx->time_base = dec_ctx->time_base;
+    }
+
+    if (ost->avg_frame_rate.num)
+        enc_ctx->time_base = av_inv_q(ost->avg_frame_rate);
+
+    av_reduce(&enc_ctx->time_base.num, &enc_ctx->time_base.den,
+              enc_ctx->time_base.num, enc_ctx->time_base.den, INT_MAX);
+
+    return 0;
+}
diff --git a/libavformat/version.h b/libavformat/version.h
index 90ac534a99..34226cae20 100644
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -32,8 +32,8 @@
 // Major bumping may affect Ticket5467, 5421, 5451(compatibility with Chromium)
 // Also please add any ticket numbers that you believe might be affected here
 #define LIBAVFORMAT_VERSION_MAJOR  57
-#define LIBAVFORMAT_VERSION_MINOR  48
-#define LIBAVFORMAT_VERSION_MICRO 103
+#define LIBAVFORMAT_VERSION_MINOR  49
+#define LIBAVFORMAT_VERSION_MICRO 100
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
                                                LIBAVFORMAT_VERSION_MINOR, \