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ffmpeg
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ring buffer fix by (Luca Abeni <lucabe72 at email dot it>) 

Originally committed as revision 3067 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2004-04-25 13:30:21 +00:00
parent 92a69cf868
commit 7aae316869
1 changed files with 13 additions and 8 deletions
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21
libavformat/grab.c
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@ -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;
}