lavc: add frame multithreading capability (currently intra only)

Compared to the decoder side, this code is able to change both the
delay and the number of threads seamlessly during encoding. Also
any idle thread can pick up tasks, the strict round robin in order
limit is gone too.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/Makefile

@@ -760,9 +760,9 @@ OBJS-$(CONFIG_REMOVE_EXTRADATA_BSF)       += remove_extradata_bsf.o
 OBJS-$(CONFIG_TEXT2MOVSUB_BSF)            += movsub_bsf.o
 
 # thread libraries
-OBJS-$(HAVE_PTHREADS)                  += pthread.o
-OBJS-$(HAVE_W32THREADS)                += pthread.o
-OBJS-$(HAVE_OS2THREADS)                += pthread.o
+OBJS-$(HAVE_PTHREADS)                  += pthread.o frame_thread_encoder.o
+OBJS-$(HAVE_W32THREADS)                += pthread.o frame_thread_encoder.o
+OBJS-$(HAVE_OS2THREADS)                += pthread.o frame_thread_encoder.o
 
 # inverse.o contains the ff_inverse table definition, which is used by
 # the FASTDIV macro (from libavutil); since referencing the external

libavcodec/frame_thread_encoder.c

+/*
+ * Copyright (c) 2012 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "frame_thread_encoder.h"
+
+#include "libavutil/fifo.h"
+#include "libavutil/avassert.h"
+#include "libavutil/imgutils.h"
+#include "avcodec.h"
+#include "internal.h"
+#include "thread.h"
+
+#if HAVE_PTHREADS
+#include <pthread.h>
+#elif HAVE_W32THREADS
+#include "w32pthreads.h"
+#elif HAVE_OS2THREADS
+#include "os2threads.h"
+#endif
+
+#define MAX_THREADS 64
+#define BUFFER_SIZE (2*MAX_THREADS)
+
+typedef struct{
+    void *indata;
+    void *outdata;
+    int64_t return_code;
+    unsigned index;
+} Task;
+
+typedef struct{
+    AVCodecContext *parent_avctx;
+    pthread_mutex_t buffer_mutex;
+
+    AVFifoBuffer *task_fifo;
+    pthread_mutex_t task_fifo_mutex;
+    pthread_cond_t task_fifo_cond;
+
+    Task finished_tasks[BUFFER_SIZE];
+    pthread_mutex_t finished_task_mutex;
+    pthread_cond_t finished_task_cond;
+
+    unsigned task_index;
+    unsigned finished_task_index;
+
+    pthread_t worker[MAX_THREADS];
+    int exit;
+} ThreadContext;
+
+static void * attribute_align_arg worker(void *v){
+    AVCodecContext *avctx = v;
+    ThreadContext *c = avctx->internal->frame_thread_encoder;
+    AVPacket *pkt = NULL;
+
+    while(!c->exit){
+        int got_packet, ret;
+        AVFrame *frame;
+        Task task;
+
+        if(!pkt) pkt= av_mallocz(sizeof(*pkt));
+        if(!pkt) continue;
+        av_init_packet(pkt);
+
+        pthread_mutex_lock(&c->task_fifo_mutex);
+        while (av_fifo_size(c->task_fifo) <= 0 || c->exit) {
+            if(c->exit){
+                pthread_mutex_unlock(&c->task_fifo_mutex);
+                goto end;
+            }
+            pthread_cond_wait(&c->task_fifo_cond, &c->task_fifo_mutex);
+        }
+        av_fifo_generic_read(c->task_fifo, &task, sizeof(task), NULL);
+        pthread_mutex_unlock(&c->task_fifo_mutex);
+        frame = task.indata;
+
+        ret = avcodec_encode_video2(avctx, pkt, frame, &got_packet);
+        pthread_mutex_lock(&c->buffer_mutex);
+        c->parent_avctx->release_buffer(c->parent_avctx, frame);
+        pthread_mutex_unlock(&c->buffer_mutex);
+        av_freep(&frame);
+        if(!got_packet)
+            continue;
+        av_dup_packet(pkt);
+        pthread_mutex_lock(&c->finished_task_mutex);
+        c->finished_tasks[task.index].outdata = pkt; pkt = NULL;
+        c->finished_tasks[task.index].return_code = ret;
+        pthread_cond_signal(&c->finished_task_cond);
+        pthread_mutex_unlock(&c->finished_task_mutex);
+    }
+end:
+    av_free(pkt);
+    pthread_mutex_lock(&c->buffer_mutex);
+    avcodec_close(avctx);
+    pthread_mutex_unlock(&c->buffer_mutex);
+    av_freep(&avctx);
+    return NULL;
+}
+
+int ff_frame_thread_encoder_init(AVCodecContext *avctx){
+    int i=0;
+    ThreadContext *c;
+
+
+    if(   !(avctx->thread_type & FF_THREAD_FRAME)
+       || !(avctx->codec->capabilities & CODEC_CAP_INTRA_ONLY))
+        return 0;
+
+    if(!avctx->thread_count) {
+        avctx->thread_count = ff_get_logical_cpus(avctx);
+        avctx->thread_count = FFMIN(avctx->thread_count, MAX_THREADS);
+    }
+
+    if(avctx->thread_count <= 1)
+        return 0;
+
+    if(avctx->thread_count > MAX_THREADS)
+        return AVERROR(EINVAL);
+
+    av_assert0(!avctx->internal->frame_thread_encoder);
+    c = avctx->internal->frame_thread_encoder = av_mallocz(sizeof(ThreadContext));
+    if(!c)
+        return AVERROR(ENOMEM);
+
+    c->parent_avctx = avctx;
+
+    c->task_fifo = av_fifo_alloc(sizeof(Task) * BUFFER_SIZE);
+    if(!c->task_fifo)
+        goto fail;
+
+    pthread_mutex_init(&c->task_fifo_mutex, NULL);
+    pthread_mutex_init(&c->finished_task_mutex, NULL);
+    pthread_mutex_init(&c->buffer_mutex, NULL);
+    pthread_cond_init(&c->task_fifo_cond, NULL);
+    pthread_cond_init(&c->finished_task_cond, NULL);
+
+    for(i=0; i<avctx->thread_count ; i++){
+        AVCodecContext *thread_avctx = avcodec_alloc_context3(avctx->codec);
+        if(!thread_avctx)
+            goto fail;
+        *thread_avctx = *avctx;
+        thread_avctx->internal = NULL;
+        thread_avctx->priv_data = av_malloc(avctx->codec->priv_data_size);
+        if(!thread_avctx->priv_data) {
+            av_freep(&thread_avctx);
+            goto fail;
+        }
+        memcpy(thread_avctx->priv_data, avctx->priv_data, avctx->codec->priv_data_size);
+        thread_avctx->thread_count = 1;
+        thread_avctx->active_thread_type &= ~FF_THREAD_FRAME;
+
+        //FIXME pass private options to encoder
+        if(avcodec_open2(thread_avctx, avctx->codec, NULL) < 0) {
+            goto fail;
+        }
+        av_assert0(!thread_avctx->internal->frame_thread_encoder);
+        thread_avctx->internal->frame_thread_encoder = c;
+        if(pthread_create(&c->worker[i], NULL, worker, thread_avctx)) {
+            goto fail;
+        }
+    }
+
+    avctx->active_thread_type = FF_THREAD_FRAME;
+
+    return 0;
+fail:
+    avctx->thread_count = i;
+    av_log(avctx, AV_LOG_ERROR, "ff_frame_thread_encoder_init failed\n");
+    ff_frame_thread_encoder_free(avctx);
+    return -1;
+}
+
+void ff_frame_thread_encoder_free(AVCodecContext *avctx){
+    int i;
+    ThreadContext *c= avctx->internal->frame_thread_encoder;
+
+    pthread_mutex_lock(&c->task_fifo_mutex);
+    c->exit = 1;
+    pthread_cond_broadcast(&c->task_fifo_cond);
+    pthread_mutex_unlock(&c->task_fifo_mutex);
+
+    for (i=0; i<avctx->thread_count; i++) {
+         pthread_join(c->worker[i], NULL);
+    }
+
+    pthread_mutex_destroy(&c->task_fifo_mutex);
+    pthread_mutex_destroy(&c->finished_task_mutex);
+    pthread_mutex_destroy(&c->buffer_mutex);
+    pthread_cond_destroy(&c->task_fifo_cond);
+    pthread_cond_destroy(&c->finished_task_cond);
+    av_fifo_free(c->task_fifo); c->task_fifo = NULL;
+    av_freep(&avctx->internal->frame_thread_encoder);
+}
+
+int ff_thread_video_encode_frame(AVCodecContext *avctx, AVPacket *pkt, const AVFrame *frame, int *got_packet_ptr){
+    ThreadContext *c = avctx->internal->frame_thread_encoder;
+    Task task;
+    int ret;
+
+    av_assert1(!*got_packet_ptr);
+
+    if(frame){
+        if(!(avctx->flags & CODEC_FLAG_INPUT_PRESERVED)){
+            AVFrame *new = avcodec_alloc_frame();
+            if(!new)
+                return AVERROR(ENOMEM);
+            pthread_mutex_lock(&c->buffer_mutex);
+            ret = c->parent_avctx->get_buffer(c->parent_avctx, new);
+            pthread_mutex_unlock(&c->buffer_mutex);
+            if(ret<0)
+                return ret;
+            new->pts = frame->pts;
+            av_image_copy(new->data, new->linesize, (const uint8_t **)frame->data, frame->linesize,
+                          avctx->pix_fmt, avctx->width, avctx->height);
+            frame = new;
+        }
+
+        task.index = c->task_index;
+        task.indata = (void*)frame;
+        pthread_mutex_lock(&c->task_fifo_mutex);
+        av_fifo_generic_write(c->task_fifo, &task, sizeof(task), NULL);
+        pthread_cond_signal(&c->task_fifo_cond);
+        pthread_mutex_unlock(&c->task_fifo_mutex);
+
+        c->task_index = (c->task_index+1) % BUFFER_SIZE;
+
+        if(!c->finished_tasks[c->finished_task_index].outdata && (c->task_index - c->finished_task_index) % BUFFER_SIZE <= avctx->thread_count)
+            return 0;
+    }
+
+    if(c->task_index == c->finished_task_index)
+        return 0;
+
+    pthread_mutex_lock(&c->finished_task_mutex);
+    while (!c->finished_tasks[c->finished_task_index].outdata) {
+        pthread_cond_wait(&c->finished_task_cond, &c->finished_task_mutex);
+    }
+    task = c->finished_tasks[c->finished_task_index];
+    *pkt = *(AVPacket*)(task.outdata);
+    c->finished_tasks[c->finished_task_index].outdata= NULL;
+    c->finished_task_index = (c->finished_task_index+1) % BUFFER_SIZE;
+    pthread_mutex_unlock(&c->finished_task_mutex);
+
+    *got_packet_ptr = 1;
+
+    return task.return_code;
+}

libavcodec/frame_thread_encoder.h

+/*
+ * Copyright (c) 2012 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "avcodec.h"
+
+int ff_frame_thread_encoder_init(AVCodecContext *avctx);
+void ff_frame_thread_encoder_free(AVCodecContext *avctx);
+int ff_thread_video_encode_frame(AVCodecContext *avctx, AVPacket *pkt, const AVFrame *frame, int *got_packet_ptr);
+

libavcodec/internal.h

@@ -82,6 +82,8 @@ typedef struct AVCodecInternal {
      */
     uint8_t *byte_buffer;
     unsigned int byte_buffer_size;
+
+    void *frame_thread_encoder;
 } AVCodecInternal;
 
 struct AVCodecDefault {

libavcodec/utils.c

@@ -40,6 +40,7 @@
 #include "libavutil/opt.h"
 #include "imgconvert.h"
 #include "thread.h"
+#include "frame_thread_encoder.h"
 #include "audioconvert.h"
 #include "internal.h"
 #include "bytestream.h"
@@ -851,7 +852,14 @@ int attribute_align_arg avcodec_open2(AVCodecContext *avctx, AVCodec *codec, AVD
     if (!HAVE_THREADS)
         av_log(avctx, AV_LOG_WARNING, "Warning: not compiled with thread support, using thread emulation\n");
 
-    if (HAVE_THREADS && !avctx->thread_opaque) {
+    entangled_thread_counter--; //we will instanciate a few encoders thus kick the counter to prevent false detection of a problem
+    ret = ff_frame_thread_encoder_init(avctx);
+    entangled_thread_counter++;
+    if (ret < 0)
+        goto free_and_end;
+
+    if (HAVE_THREADS && !avctx->thread_opaque
+        && !(avctx->internal->frame_thread_encoder && (avctx->active_thread_type&FF_THREAD_FRAME))) {
         ret = ff_thread_init(avctx);
         if (ret < 0) {
             goto free_and_end;
@@ -931,7 +939,7 @@ int attribute_align_arg avcodec_open2(AVCodecContext *avctx, AVCodec *codec, AVD
     avctx->pts_correction_last_pts =
     avctx->pts_correction_last_dts = INT64_MIN;
 
-    if(avctx->codec->init && !(avctx->active_thread_type&FF_THREAD_FRAME)){
+    if(avctx->codec->init && (!(avctx->active_thread_type&FF_THREAD_FRAME) || avctx->internal->frame_thread_encoder)){
         ret = avctx->codec->init(avctx);
         if (ret < 0) {
             goto free_and_end;
@@ -1301,6 +1309,9 @@ int attribute_align_arg avcodec_encode_video2(AVCodecContext *avctx,
 
     *got_packet_ptr = 0;
 
+    if(avctx->internal->frame_thread_encoder && (avctx->active_thread_type&FF_THREAD_FRAME))
+        return ff_thread_video_encode_frame(avctx, avpkt, frame, got_packet_ptr);
+
     if (!(avctx->codec->capabilities & CODEC_CAP_DELAY) && !frame) {
         av_free_packet(avpkt);
         av_init_packet(avpkt);
@@ -1661,6 +1672,11 @@ av_cold int avcodec_close(AVCodecContext *avctx)
     }
 
     if (avcodec_is_open(avctx)) {
+        if (avctx->internal->frame_thread_encoder && avctx->thread_count > 1) {
+            entangled_thread_counter --;
+            ff_frame_thread_encoder_free(avctx);
+            entangled_thread_counter ++;
+        }
         if (HAVE_THREADS && avctx->thread_opaque)
             ff_thread_free(avctx);
         if (avctx->codec && avctx->codec->close)