[FFmpeg-devel] [PATCH 5/6] sink_buffer: implement fixed frame size.

Nicolas George nicolas.george at normalesup.org
Mon Jun 25 00:35:59 CEST 2012


Work in progress: currently, only formats where samples are packet at 8
bytes per sample work, and the padding of the last frame is not cleared.

Signed-off-by: Nicolas George <nicolas.george at normalesup.org>
---
 libavfilter/buffersink.h  |    9 +++++
 libavfilter/sink_buffer.c |   86 ++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 87 insertions(+), 8 deletions(-)

diff --git a/libavfilter/buffersink.h b/libavfilter/buffersink.h
index d92b903..b4991b4 100644
--- a/libavfilter/buffersink.h
+++ b/libavfilter/buffersink.h
@@ -59,6 +59,15 @@ typedef struct {
 AVABufferSinkParams *av_abuffersink_params_alloc(void);
 
 /**
+ * Set the frame size for an audio buffer sink.
+ *
+ * All calls to av_buffersink_get_buffer_ref will return a buffer with
+ * exactly the specified number of samples, or AVERROR(EAGAIN) if there is
+ * not enough. The last buffer at EOF will be padded with 0.
+ */
+void av_buffersink_set_frame_size(AVFilterContext *ctx, unsigned frame_size);
+
+/**
  * Tell av_buffersink_get_buffer_ref() to read video/samples buffer
  * reference, but not remove it from the buffer. This is useful if you
  * need only to read a video/samples buffer, without to fetch it.
diff --git a/libavfilter/sink_buffer.c b/libavfilter/sink_buffer.c
index 2ee3886..39ae12e 100644
--- a/libavfilter/sink_buffer.c
+++ b/libavfilter/sink_buffer.c
@@ -28,6 +28,7 @@
 #include "avfilter.h"
 #include "buffersink.h"
 #include "internal.h"
+#include "audio.h"
 
 extern AVFilter avfilter_vsink_buffersink;
 extern AVFilter avfilter_asink_abuffersink;
@@ -66,6 +67,10 @@ typedef struct {
     /* only used for audio */
     enum AVSampleFormat *sample_fmts;       ///< list of accepted sample formats, terminated by AV_SAMPLE_FMT_NONE
     int64_t *channel_layouts;               ///< list of accepted channel layouts, terminated by -1
+
+    AVFilterBufferRef *partial_buf;         ///< buffer being padded to frame_size
+    unsigned partial_buf_pos;               ///< number of samples already present
+    unsigned frame_size;                    ///< frame size, 0 if unused
 } BufferSinkContext;
 
 #define FIFO_INIT_SIZE 8
@@ -97,12 +102,10 @@ static av_cold void common_uninit(AVFilterContext *ctx)
     }
 }
 
-static void end_frame(AVFilterLink *inlink)
+static void add_frame(AVFilterContext *ctx, AVFilterBufferRef *frame)
 {
-    AVFilterContext *ctx = inlink->dst;
-    BufferSinkContext *buf = inlink->dst->priv;
+    BufferSinkContext *buf = ctx->priv;
 
-    av_assert1(inlink->cur_buf);
     if (av_fifo_space(buf->fifo) < sizeof(AVFilterBufferRef *)) {
         /* realloc fifo size */
         if (av_fifo_realloc2(buf->fifo, av_fifo_size(buf->fifo) * 2) < 0) {
@@ -115,7 +118,32 @@ static void end_frame(AVFilterLink *inlink)
 
     /* cache frame */
     av_fifo_generic_write(buf->fifo,
-                          &inlink->cur_buf, sizeof(AVFilterBufferRef *), NULL);
+                          &frame, sizeof(AVFilterBufferRef *), NULL);
+}
+
+static void end_frame(AVFilterLink *inlink)
+{
+    AVFilterContext *ctx = inlink->dst;
+
+    av_assert1(inlink->cur_buf);
+    add_frame(ctx, inlink->cur_buf);
+}
+
+void av_buffersink_set_frame_size(AVFilterContext *ctx, unsigned frame_size)
+{
+    BufferSinkContext *buf = ctx->priv;
+
+    av_assert1(ctx->filter == &avfilter_asink_abuffersink);
+    buf->frame_size = frame_size;
+}
+
+static void flush_partial_frame(AVFilterContext *ctx)
+{
+    BufferSinkContext *buf = ctx->priv;
+
+    add_frame(ctx, buf->partial_buf);
+    buf->partial_buf     = NULL;
+    buf->partial_buf_pos = 0;
 }
 
 int av_buffersink_get_buffer_ref(AVFilterContext *ctx,
@@ -132,8 +160,17 @@ int av_buffersink_get_buffer_ref(AVFilterContext *ctx,
     if (!av_fifo_size(buf->fifo)) {
         if (flags & AV_BUFFERSINK_FLAG_NO_REQUEST)
             return AVERROR(EAGAIN);
-        if ((ret = ff_request_frame(inlink)) < 0)
-            return ret;
+        if ((ret = ff_request_frame(inlink)) < 0) {
+            /* FIXME why is it not reached? */
+            if (ret == AVERROR_EOF && buf->frame_size && buf->partial_buf) {
+                av_log(0, 16, "padding last frame\n");
+                flush_partial_frame(ctx);
+                if (!av_fifo_size(buf->fifo))
+                    return AVERROR(ENOMEM);
+            } else {
+                return ret;
+            }
+        }
     }
 
     if (!av_fifo_size(buf->fifo))
@@ -240,7 +277,39 @@ AVFilter avfilter_vsink_buffersink = {
 
 static void filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref)
 {
-    end_frame(link);
+    AVFilterContext *ctx = link->dst;
+    BufferSinkContext *buf = ctx->priv;
+    unsigned insize, inpos = 0, nb_samples;
+    unsigned sample_size = 8; /* TODO (hardcoded for stereo float) */
+
+    if (!buf->frame_size) {
+        add_frame(ctx, samplesref);
+        return;
+    }
+    /* TODO move this piece of code (and the corresponding part to handle
+       EOF) into an inline function in a separate header to make it
+       available for any filter requiring fixed frames. */
+    insize = samplesref->audio->nb_samples;
+    while (insize) {
+        if (!buf->partial_buf) {
+            buf->partial_buf = ff_default_get_audio_buffer(link, AV_PERM_READ,
+                                                           buf->frame_size);
+            if (!buf->partial_buf)
+                break;
+        }
+        nb_samples = FFMIN(insize, buf->frame_size - buf->partial_buf_pos);
+        /* TODO all planes */
+        memcpy(buf->partial_buf->data[0] + buf->partial_buf_pos * sample_size,
+               samplesref      ->data[0] + inpos                * sample_size,
+               nb_samples * sample_size);
+        insize               -= nb_samples;
+        inpos                += nb_samples;
+        buf->partial_buf_pos += nb_samples;
+        if (buf->partial_buf_pos == buf->frame_size)
+            flush_partial_frame(ctx);
+    }
+    avfilter_unref_buffer(samplesref);
+    return;
 }
 
 static av_cold int asink_init(AVFilterContext *ctx, const char *args, void *opaque)
@@ -273,6 +342,7 @@ static av_cold void asink_uninit(AVFilterContext *ctx)
 
     av_freep(&buf->sample_fmts);
     av_freep(&buf->channel_layouts);
+    avfilter_unref_bufferp(&buf->partial_buf);
     common_uninit(ctx);
 }
 
-- 
1.7.10



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