[SCM] libav/experimental: ring buffer fix by (Luca Abeni <lucabe72 at email dot it>)
siretart at users.alioth.debian.org
siretart at users.alioth.debian.org
Sun Jun 30 15:40:08 UTC 2013
The following commit has been merged in the experimental branch:
commit 7aae316869feda22d86406bc900e12a5b7029c05
Author: Michael Niedermayer <michaelni at gmx.at>
Date: Sun Apr 25 13:30:21 2004 +0000
ring buffer fix by (Luca Abeni <lucabe72 at email dot it>)
Originally committed as revision 3067 to svn://svn.ffmpeg.org/ffmpeg/trunk
diff --git a/libavformat/grab.c b/libavformat/grab.c
index d8a1ce6..755680e 100644
--- a/libavformat/grab.c
+++ b/libavformat/grab.c
@@ -66,6 +66,7 @@ static int grab_read_header(AVFormatContext *s1, AVFormatParameters *ap)
struct video_tuner tuner;
struct video_audio audio;
const char *video_device;
+ int j;
if (!ap || ap->width <= 0 || ap->height <= 0 || ap->frame_rate <= 0)
return -1;
@@ -229,6 +230,10 @@ static int grab_read_header(AVFormatContext *s1, AVFormatParameters *ap)
}
goto fail;
}
+ for (j = 1; j < s->gb_buffers.frames; j++) {
+ s->gb_buf.frame = j;
+ ioctl(video_fd, VIDIOCMCAPTURE, &s->gb_buf);
+ }
s->frame_format = s->gb_buf.format;
s->use_mmap = 1;
}
@@ -273,8 +278,14 @@ static int v4l_mm_read_picture(VideoData *s, uint8_t *buf)
{
uint8_t *ptr;
+ while (ioctl(s->fd, VIDIOCSYNC, &s->gb_frame) < 0 &&
+ (errno == EAGAIN || errno == EINTR));
+
+ ptr = s->video_buf + s->gb_buffers.offsets[s->gb_frame];
+ memcpy(buf, ptr, s->frame_size);
+
/* Setup to capture the next frame */
- s->gb_buf.frame = (s->gb_frame + 1) % s->gb_buffers.frames;
+ s->gb_buf.frame = s->gb_frame;
if (ioctl(s->fd, VIDIOCMCAPTURE, &s->gb_buf) < 0) {
if (errno == EAGAIN)
av_log(NULL, AV_LOG_ERROR, "Cannot Sync\n");
@@ -283,14 +294,8 @@ static int v4l_mm_read_picture(VideoData *s, uint8_t *buf)
return -EIO;
}
- while (ioctl(s->fd, VIDIOCSYNC, &s->gb_frame) < 0 &&
- (errno == EAGAIN || errno == EINTR));
-
- ptr = s->video_buf + s->gb_buffers.offsets[s->gb_frame];
- memcpy(buf, ptr, s->frame_size);
-
/* This is now the grabbing frame */
- s->gb_frame = s->gb_buf.frame;
+ s->gb_frame = (s->gb_frame + 1) % s->gb_buffers.frames;
return s->frame_size;
}
--
Libav/FFmpeg packaging
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