[FFmpeg-devel] [PATCH v7] avcodec/v210dec: add the frame and slice threading support

lance.lmwang at gmail.com lance.lmwang at gmail.com
Fri Oct 18 04:15:09 EEST 2019


From: Limin Wang <lance.lmwang at gmail.com>

Threading is to avoid a core cpu being occupied fully with other filters like scale,
regarding performance, if your cpu frequency is very high, the gain is very small, but
with more cores and fewer cpu MHz cpus, you will get more improvements.

The following is my testing results of performance on two different system:
1, testing result with my old mac pro
./ffmpeg -y -i ./4k_4096_3072.mov -c:v v210 -f rawvideo -frames 10 ./1.v210

./ffmpeg -threads 1 -s 4096x3072 -stream_loop 100 -i ./1.v210 -benchmark -f null -
frame= 1010 fps= 42 q=-0.0 Lsize=N/A time=00:00:40.40 bitrate=N/A speed=1.69x

patch applied:
./ffmpeg -threads 4 -thread_type frame+slice  -s 4096x3072 -stream_loop 100 -i ./1.v210 -benchmark -f null -
frame= 1010 fps= 55 q=-0.0 Lsize=N/A time=00:00:40.40 bitrate=N/A speed=2.22x

2, testing result with x86 server (Intel(R) Xeon(R) CPU E5-2650 v2 @ 2.60GHz):
./ffmpeg  -y -i ./4k_3840_2160.ts -c:v v210 -f rawvideo -frames 50 ./2.v210

./ffmpeg -threads 1 -s 3840x2160  -stream_loop 20 -i ./2.v210 -benchmark -f null -
frame= 1050 fps= 80 q=-0.0 Lsize=N/A time=00:00:42.00 bitrate=N/A speed=3.19x

patch applied:
./ffmpeg -threads 2 -thread_type frame+slice  -s 3840x2160  -stream_loop 20 -i ./2.v210 -benchmark -f null -
frame= 1050 fps=111 q=-0.0 Lsize=N/A time=00:00:42.00 bitrate=N/A speed=4.45x

./ffmpeg -threads 4 -thread_type frame+slice  -s 3840x2160  -stream_loop 20 -i ./2.v210 -benchmark -f null -
frame= 1050 fps=145 q=-0.0 Lsize=N/A time=00:00:42.00 bitrate=N/A speed=5.81x

Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
---
 libavcodec/v210dec.c | 126 ++++++++++++++++++++++++++-----------------
 libavcodec/v210dec.h |   1 +
 2 files changed, 79 insertions(+), 48 deletions(-)

diff --git a/libavcodec/v210dec.c b/libavcodec/v210dec.c
index 5a33d8c089..4b436d2fa0 100644
--- a/libavcodec/v210dec.c
+++ b/libavcodec/v210dec.c
@@ -28,6 +28,7 @@
 #include "libavutil/internal.h"
 #include "libavutil/mem.h"
 #include "libavutil/intreadwrite.h"
+#include "thread.h"
 
 #define READ_PIXELS(a, b, c)         \
     do {                             \
@@ -37,6 +38,12 @@
         *c++ = (val >> 20) & 0x3FF;  \
     } while (0)
 
+typedef struct ThreadData {
+    AVFrame *frame;
+    uint8_t *buf;
+    int stride;
+} ThreadData;
+
 static void v210_planar_unpack_c(const uint32_t *src, uint16_t *y, uint16_t *u, uint16_t *v, int width)
 {
     uint32_t val;
@@ -64,21 +71,81 @@ static av_cold int decode_init(AVCodecContext *avctx)
     avctx->pix_fmt             = AV_PIX_FMT_YUV422P10;
     avctx->bits_per_raw_sample = 10;
 
+    s->thread_count  = av_clip(avctx->thread_count, 1, avctx->height/4);
     s->aligned_input = 0;
     ff_v210dec_init(s);
 
     return 0;
 }
 
+static int v210_decode_slice(AVCodecContext *avctx, void *arg, int jobnr, int threadnr)
+{
+    V210DecContext *s = avctx->priv_data;
+    int h, w;
+    ThreadData *td = arg;
+    AVFrame *frame = td->frame;
+    int stride = td->stride;
+    int slice_start =  (avctx->height *  jobnr   ) / s->thread_count;
+    int slice_end = (avctx->height * (jobnr+1)) / s->thread_count;
+    uint8_t *psrc = td->buf + stride * slice_start;
+    uint16_t *y, *u, *v;
+
+    y = (uint16_t*)frame->data[0] + slice_start * frame->linesize[0] / 2;
+    u = (uint16_t*)frame->data[1] + slice_start * frame->linesize[1] / 2;
+    v = (uint16_t*)frame->data[2] + slice_start * frame->linesize[2] / 2;
+    for (h = slice_start; h < slice_end; h++) {
+        const uint32_t *src = (const uint32_t*)psrc;
+        uint32_t val;
+
+        w = (avctx->width / 12) * 12;
+        s->unpack_frame(src, y, u, v, w);
+
+        y += w;
+        u += w >> 1;
+        v += w >> 1;
+        src += (w << 1) / 3;
+
+        if (w < avctx->width - 5) {
+            READ_PIXELS(u, y, v);
+            READ_PIXELS(y, u, y);
+            READ_PIXELS(v, y, u);
+            READ_PIXELS(y, v, y);
+            w += 6;
+        }
+
+        if (w < avctx->width - 1) {
+            READ_PIXELS(u, y, v);
+
+            val  = av_le2ne32(*src++);
+            *y++ =  val & 0x3FF;
+            if (w < avctx->width - 3) {
+                *u++ = (val >> 10) & 0x3FF;
+                *y++ = (val >> 20) & 0x3FF;
+
+                val  = av_le2ne32(*src++);
+                *v++ =  val & 0x3FF;
+                *y++ = (val >> 10) & 0x3FF;
+            }
+        }
+
+        psrc += stride;
+        y += frame->linesize[0] / 2 - avctx->width + (avctx->width & 1);
+        u += frame->linesize[1] / 2 - avctx->width / 2;
+        v += frame->linesize[2] / 2 - avctx->width / 2;
+    }
+
+    return 0;
+}
+
 static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
                         AVPacket *avpkt)
 {
     V210DecContext *s = avctx->priv_data;
-
-    int h, w, ret, stride, aligned_input;
+    ThreadData td;
+    int ret, stride, aligned_input;
+    ThreadFrame frame = { .f = data };
     AVFrame *pic = data;
     const uint8_t *psrc = avpkt->data;
-    uint16_t *y, *u, *v;
 
     if (s->custom_stride )
         stride = s->custom_stride;
@@ -86,6 +153,7 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
         int aligned_width = ((avctx->width + 47) / 48) * 48;
         stride = aligned_width * 8 / 3;
     }
+    td.stride = stride;
 
     if (avpkt->size < stride * avctx->height) {
         if ((((avctx->width + 23) / 24) * 24 * 8) / 3 * avctx->height == avpkt->size) {
@@ -110,55 +178,15 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
         ff_v210dec_init(s);
     }
 
-    if ((ret = ff_get_buffer(avctx, pic, 0)) < 0)
+    if ((ret = ff_thread_get_buffer(avctx, &frame, 0)) < 0)
         return ret;
 
-    y = (uint16_t*)pic->data[0];
-    u = (uint16_t*)pic->data[1];
-    v = (uint16_t*)pic->data[2];
     pic->pict_type = AV_PICTURE_TYPE_I;
     pic->key_frame = 1;
 
-    for (h = 0; h < avctx->height; h++) {
-        const uint32_t *src = (const uint32_t*)psrc;
-        uint32_t val;
-
-        w = (avctx->width / 12) * 12;
-        s->unpack_frame(src, y, u, v, w);
-
-        y += w;
-        u += w >> 1;
-        v += w >> 1;
-        src += (w << 1) / 3;
-
-        if (w < avctx->width - 5) {
-            READ_PIXELS(u, y, v);
-            READ_PIXELS(y, u, y);
-            READ_PIXELS(v, y, u);
-            READ_PIXELS(y, v, y);
-            w += 6;
-        }
-
-        if (w < avctx->width - 1) {
-            READ_PIXELS(u, y, v);
-
-            val  = av_le2ne32(*src++);
-            *y++ =  val & 0x3FF;
-            if (w < avctx->width - 3) {
-                *u++ = (val >> 10) & 0x3FF;
-                *y++ = (val >> 20) & 0x3FF;
-
-                val  = av_le2ne32(*src++);
-                *v++ =  val & 0x3FF;
-                *y++ = (val >> 10) & 0x3FF;
-            }
-        }
-
-        psrc += stride;
-        y += pic->linesize[0] / 2 - avctx->width + (avctx->width & 1);
-        u += pic->linesize[1] / 2 - avctx->width / 2;
-        v += pic->linesize[2] / 2 - avctx->width / 2;
-    }
+    td.buf = (uint8_t*)psrc;
+    td.frame = pic;
+    avctx->execute2(avctx, v210_decode_slice, &td, NULL, s->thread_count);
 
     if (avctx->field_order > AV_FIELD_PROGRESSIVE) {
         /* we have interlaced material flagged in container */
@@ -194,6 +222,8 @@ AVCodec ff_v210_decoder = {
     .priv_data_size = sizeof(V210DecContext),
     .init           = decode_init,
     .decode         = decode_frame,
-    .capabilities   = AV_CODEC_CAP_DR1,
+    .capabilities   = AV_CODEC_CAP_DR1 |
+                      AV_CODEC_CAP_SLICE_THREADS |
+                      AV_CODEC_CAP_FRAME_THREADS,
     .priv_class     = &v210dec_class,
 };
diff --git a/libavcodec/v210dec.h b/libavcodec/v210dec.h
index cfdb29da09..662e266315 100644
--- a/libavcodec/v210dec.h
+++ b/libavcodec/v210dec.h
@@ -27,6 +27,7 @@ typedef struct {
     AVClass *av_class;
     int custom_stride;
     int aligned_input;
+    int thread_count;
     int stride_warning_shown;
     void (*unpack_frame)(const uint32_t *src, uint16_t *y, uint16_t *u, uint16_t *v, int width);
 } V210DecContext;
-- 
2.21.0



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