[Ffmpeg-devel] [PATCH] grabbing with V4L
Flavio Pimentel Duarte
flaviop
Tue Feb 21 12:24:05 CET 2006
Sorry Luca!
Although the last patch I sent works it was solving the problem
in an ugly way. This one is more adequate.
Flavio P. Duarte
On Mon, 20 Feb 2006, Flavio Pimentel Duarte wrote:
>
>
> On Fri, 17 Feb 2006, Luca Abeni wrote:
>
>> Hi Flavio,
>>
>> On Wed, 2006-02-15 at 14:34 +0100, Luca Abeni wrote:
>> [...]
>> > > The patch I've sent didn't create a single new line, it only moves
>> > > some
>> > > image settings initialization to outside the if statement. It was also
>> > > not my idea, I borrowed from mplayer ;)
>> > Yes, looking at the patch I agree that it should not create problems.
>> > I'll test it tomorrow, just as a confirmation.
>> I tested your patch, and verified that it does not create any regression.
>> Uhmm... I still do not understand why it is needed by your webcam driver
>> but the "regular" bttv driver does not need it...
>>
>> Anyway, I think your patch is good because it permits to avoid some code
>> duplication (in fact, after applying your patch all the code around line
>> 212 becomes useless). So, I went ahead and I removed some code that (I
>> think) is obsoleted by your patch (since desired_palette is already set
>> by previous code).
>>
>> Does the attached patch (your patch + some useless code removal) work
>> for you?
> The patch you sent me did not work. It issues the following error:
> $ ./ffmpeg -s 320x240 -an -vd /dev/video0 output.mpg
> FFmpeg version CVS, Copyright (c) 2000-2004 Fabrice Bellard
> configuration: --disable-v4l2
> libavutil version: 49.0.0
> libavcodec version: 51.7.0
> libavformat version: 50.3.0
> built on Feb 20 2006 11:05:32, gcc: 3.4.3 (Mandrakelinux 10.2
> 3.4.3-7mdk)
> File 'output.mpg' already exists. Overwrite ? [y/N] y
> [video4linux @ 0x82c8ef4]Fatal: grab device does not support suitable format
> Could not find video grab device
>
> I had to add just one line to make it work. The modified patch is
> attached.
>
> I also have one question: how do I force ffmpeg to use v4l instead
> v4l2 ? Is there an option for it ? In my tests I had to compile ffmpeg using
> '--disable-v4l2' option, otherwise it uses v4l2.
>
>
> Flavio
>
-------------- next part --------------
--- ffmpeg/libavformat/grab.c 2006-02-01 09:31:33.000000000 -0200
+++ ffmpeg.new/libavformat/grab.c 2006-02-20 21:35:34.340312168 -0300
@@ -65,6 +65,7 @@ static int grab_read_header(AVFormatCont
int desired_palette;
struct video_tuner tuner;
struct video_audio audio;
+ struct video_picture pict;
const char *video_device;
int j;
@@ -135,11 +136,36 @@ static int grab_read_header(AVFormatCont
audio.flags &= ~VIDEO_AUDIO_MUTE;
ioctl(video_fd, VIDIOCSAUDIO, &audio);
+ ioctl(video_fd, VIDIOCGPICT, &pict);
+#if 0
+ printf("v4l: colour=%d hue=%d brightness=%d constrast=%d whiteness=%d\n",
+ pict.colour,
+ pict.hue,
+ pict.brightness,
+ pict.contrast,
+ pict.whiteness);
+#endif
+ /* try to choose a suitable video format */
+ pict.palette = desired_palette;
+ if (desired_palette == -1 || (ret = ioctl(video_fd, VIDIOCSPICT, &pict)) < 0) {
+ pict.palette=VIDEO_PALETTE_YUV420P;
+ ret = ioctl(video_fd, VIDIOCSPICT, &pict);
+ if (ret < 0) {
+ pict.palette=VIDEO_PALETTE_YUV422;
+ ret = ioctl(video_fd, VIDIOCSPICT, &pict);
+ if (ret < 0) {
+ pict.palette=VIDEO_PALETTE_RGB24;
+ ret = ioctl(video_fd, VIDIOCSPICT, &pict);
+ if (ret < 0)
+ goto fail1;
+ }
+ }
+ }
+
ret = ioctl(video_fd,VIDIOCGMBUF,&s->gb_buffers);
if (ret < 0) {
/* try to use read based access */
struct video_window win;
- struct video_picture pict;
int val;
win.x = 0;
@@ -151,32 +177,6 @@ static int grab_read_header(AVFormatCont
ioctl(video_fd, VIDIOCSWIN, &win);
- ioctl(video_fd, VIDIOCGPICT, &pict);
-#if 0
- printf("v4l: colour=%d hue=%d brightness=%d constrast=%d whiteness=%d\n",
- pict.colour,
- pict.hue,
- pict.brightness,
- pict.contrast,
- pict.whiteness);
-#endif
- /* try to choose a suitable video format */
- pict.palette = desired_palette;
- if (desired_palette == -1 || (ret = ioctl(video_fd, VIDIOCSPICT, &pict)) < 0) {
- pict.palette=VIDEO_PALETTE_YUV420P;
- ret = ioctl(video_fd, VIDIOCSPICT, &pict);
- if (ret < 0) {
- pict.palette=VIDEO_PALETTE_YUV422;
- ret = ioctl(video_fd, VIDIOCSPICT, &pict);
- if (ret < 0) {
- pict.palette=VIDEO_PALETTE_RGB24;
- ret = ioctl(video_fd, VIDIOCSPICT, &pict);
- if (ret < 0)
- goto fail1;
- }
- }
- }
-
s->frame_format = pict.palette;
val = 1;
@@ -207,24 +207,9 @@ static int grab_read_header(AVFormatCont
s->gb_buf.frame = s->gb_frame % s->gb_buffers.frames;
s->gb_buf.height = height;
s->gb_buf.width = width;
- s->gb_buf.format = desired_palette;
-
- if (desired_palette == -1 || (ret = ioctl(video_fd, VIDIOCMCAPTURE, &s->gb_buf)) < 0) {
- s->gb_buf.format = VIDEO_PALETTE_YUV420P;
+ s->gb_buf.format = pict.palette;
- ret = ioctl(video_fd, VIDIOCMCAPTURE, &s->gb_buf);
- if (ret < 0 && errno != EAGAIN) {
- /* try YUV422 */
- s->gb_buf.format = VIDEO_PALETTE_YUV422;
-
- ret = ioctl(video_fd, VIDIOCMCAPTURE, &s->gb_buf);
- if (ret < 0 && errno != EAGAIN) {
- /* try RGB24 */
- s->gb_buf.format = VIDEO_PALETTE_RGB24;
- ret = ioctl(video_fd, VIDIOCMCAPTURE, &s->gb_buf);
- }
- }
- }
+ ret = ioctl(video_fd, VIDIOCMCAPTURE, &s->gb_buf);
if (ret < 0) {
if (errno != EAGAIN) {
fail1:
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