[FFmpeg-devel] [PATCH, RFC 2/2] fftools/ffmpeg: add dynamic resolution encode support for libvpx-vp9

[Linjie Fu]

According to spec, vp9 should support dynamic resolution changes.

Add dynamic resolution encoding support in libvpx-vp9, and flush
encoders when resolution change happens.

Format change should also be supported, but I didn't test it so just
leave it open.

cmdline:
ffmpeg -noautoscale -y -i ./reinit-large_420_8-to-small_420_8.h264
     -pix_fmt yuv420p -c:v libvpx-vp9 lena.ivf

Signed-off-by: Linjie Fu <linjie.fu at intel.com>
---
 fftools/ffmpeg.c       | 9 +++++++++
 libavcodec/libvpxenc.c | 9 +++++++++
 2 files changed, 18 insertions(+)

diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
index 5d52430..e091117 100644
--- a/fftools/ffmpeg.c
+++ b/fftools/ffmpeg.c
@@ -64,6 +64,7 @@
 #include "libavutil/thread.h"
 #include "libavutil/threadmessage.h"
 #include "libavcodec/mathops.h"
+#include "libavcodec/internal.h"
 #include "libavformat/os_support.h"
 
 # include "libavfilter/avfilter.h"
@@ -130,6 +131,7 @@ static void do_video_stats(OutputStream *ost, int frame_size);
 static BenchmarkTimeStamps get_benchmark_time_stamps(void);
 static int64_t getmaxrss(void);
 static int ifilter_has_all_input_formats(FilterGraph *fg);
+static void flush_encoders(void);
 
 static int run_as_daemon  = 0;
 static int nb_frames_dup = 0;
@@ -1067,6 +1069,13 @@ static void do_video_out(OutputFile *of,
     InputStream *ist = NULL;
     AVFilterContext *filter = ost->filter->filter;
 
+    /* flush encoders in dynamic resolution encode */
+    if (next_picture && (enc->width != next_picture->width ||
+                         enc->height != next_picture->height)) {
+        flush_encoders();
+        enc->internal->draining = 0;
+    }
+
     if (ost->source_index >= 0)
         ist = input_streams[ost->source_index];
 
diff --git a/libavcodec/libvpxenc.c b/libavcodec/libvpxenc.c
index feb52ea..54ac365 100644
--- a/libavcodec/libvpxenc.c
+++ b/libavcodec/libvpxenc.c
@@ -1067,6 +1067,15 @@ static int vpx_encode(AVCodecContext *avctx, AVPacket *pkt,
     int res, coded_size;
     vpx_enc_frame_flags_t flags = 0;
 
+    if (frame && (avctx->width != frame->width ||
+                  avctx->height != frame->height)) {
+        avctx->width  = frame->width;
+        avctx->height = frame->height;
+
+        avctx->codec->close(avctx);
+        avctx->codec->init(avctx);
+    }
+
     if (frame) {
         rawimg                      = &ctx->rawimg;
         rawimg->planes[VPX_PLANE_Y] = frame->data[0];
-- 
2.7.4