[FFmpeg-devel] libavformat and video4linux2 acquire problems

[Luca Abeni]

Hi Limin,

Limin Wang wrote:
[...]
>> If you provide a patch, and it does not break dv capturing or similar 
>> things, I'll be very happy to apply it.
> 
> Please review the attached patch
Thanks. I'll have a look tonight, and I'll commit tomorrow.

> I have check dv1394, it'll not break if standard is NULL and input is -1 case.
Uhmm... I did not try, but I see this code in dv1394.c:
  if (ap->standard && !strcasecmp(ap->standard, "pal"))
         dv->format = DV1394_PAL;
     else
         dv->format = DV1394_NTSC;

     if (ap->channel)
         dv->channel = ap->channel;
     else
         dv->channel = DV1394_DEFAULT_CHANNEL;

So, standard==NULL should not be a problem (unless strcasecmp() crashes 
if the first parameter is NULL --- I'll check that), but channel == -1 
can be a problem, because dv->channel will be set to -1 instead of 
DV1394_DEFAULT_CHANNEL. But I do not know what this would imply...

So, maybe the safest thing is to remove the "video_channel = -1" part 
from your patch... I'll think about it later.


			Thanks,
				Luca
> 
> 
> Thanks,
> Limin
> 
> 
> 
> 
> ------------------------------------------------------------------------
> 
> Index: ffmpeg.c
> ===================================================================
> --- ffmpeg.c	(revision 8950)
> +++ ffmpeg.c	(working copy)
> @@ -181,8 +181,8 @@
>  
>  static int rate_emu = 0;
>  
> -static int  video_channel = 0;
> -static char *video_standard = "ntsc";
> +static int  video_channel = -1;
> +static char *video_standard;
>  
>  static int audio_volume = 256;
>  
> @@ -3833,7 +3833,8 @@
>      av_free(vstats_filename);
>  
>      av_free(opt_names);
> -
> +    av_free(video_standard);
> +    
>  #ifdef CONFIG_POWERPC_PERF
>      extern void powerpc_display_perf_report(void);
>      powerpc_display_perf_report();
> Index: libavformat/v4l2.c
> ===================================================================
> --- libavformat/v4l2.c	(revision 8950)
> +++ libavformat/v4l2.c	(working copy)
> @@ -429,47 +429,51 @@
>      struct v4l2_standard standard;
>      int i;
>  
> -    /* set tv video input */
> -    memset (&input, 0, sizeof (input));
> -    input.index = ap->channel;
> -    if(ioctl (s->fd, VIDIOC_ENUMINPUT, &input) < 0) {
> -        av_log(s1, AV_LOG_ERROR, "The V4L2 driver ioctl enum input failed:\n");
> -        return AVERROR_IO;
> -    }
> +    if(ap->channel>=0) {
> +        /* set tv video input */
> +        memset (&input, 0, sizeof (input));
> +        input.index = ap->channel;
> +        if(ioctl (s->fd, VIDIOC_ENUMINPUT, &input) < 0) {
> +            av_log(s1, AV_LOG_ERROR, "The V4L2 driver ioctl enum input failed:\n");
> +            return AVERROR_IO;
> +        }
>  
> -    av_log(s1, AV_LOG_DEBUG, "The V4L2 driver set input_id: %d, input: %s\n",
> -           ap->channel, input.name);
> -    if(ioctl (s->fd, VIDIOC_S_INPUT, &input.index) < 0 ) {
> -        av_log(s1, AV_LOG_ERROR, "The V4L2 driver ioctl set input(%d) failed\n",
> -            ap->channel);
> -        return AVERROR_IO;
> +        av_log(s1, AV_LOG_DEBUG, "The V4L2 driver set input_id: %d, input: %s\n",
> +               ap->channel, input.name);
> +        if(ioctl (s->fd, VIDIOC_S_INPUT, &input.index) < 0 ) {
> +            av_log(s1, AV_LOG_ERROR, "The V4L2 driver ioctl set input(%d) failed\n",
> +                   ap->channel);
> +            return AVERROR_IO;
> +        }
>      }
>  
> -    av_log(s1, AV_LOG_DEBUG, "The V4L2 driver set standard: %s\n",
> -           ap->standard );
> -    /* set tv standard */
> -    memset (&standard, 0, sizeof (standard));
> -    for(i=0;;i++) {
> -        standard.index = i;
> -        if (ioctl(s->fd, VIDIOC_ENUMSTD, &standard) < 0) {
> +    if(ap->standard) {
> +        av_log(s1, AV_LOG_DEBUG, "The V4L2 driver set standard: %s\n",
> +               ap->standard );
> +        /* set tv standard */
> +        memset (&standard, 0, sizeof (standard));
> +        for(i=0;;i++) {
> +            standard.index = i;
> +            if (ioctl(s->fd, VIDIOC_ENUMSTD, &standard) < 0) {
> +                av_log(s1, AV_LOG_ERROR, "The V4L2 driver ioctl set standard(%s) failed\n",
> +                       ap->standard);
> +                return AVERROR_IO;
> +            }
> +
> +            if(!strcasecmp(standard.name, ap->standard)) {
> +                break;
> +            }
> +        }
> +
> +        av_log(s1, AV_LOG_DEBUG, "The V4L2 driver set standard: %s, id: %"PRIu64"\n",
> +               ap->standard, standard.id);
> +        if (ioctl(s->fd, VIDIOC_S_STD, &standard.id) < 0) {
>              av_log(s1, AV_LOG_ERROR, "The V4L2 driver ioctl set standard(%s) failed\n",
>                     ap->standard);
>              return AVERROR_IO;
>          }
> -
> -        if(!strcasecmp(standard.name, ap->standard)) {
> -            break;
> -        }
>      }
>  
> -    av_log(s1, AV_LOG_DEBUG, "The V4L2 driver set standard: %s, id: %"PRIu64"\n",
> -           ap->standard, standard.id);
> -    if (ioctl(s->fd, VIDIOC_S_STD, &standard.id) < 0) {
> -        av_log(s1, AV_LOG_ERROR, "The V4L2 driver ioctl set standard(%s) failed\n",
> -            ap->standard);
> -        return AVERROR_IO;
> -    }
> -
>      return 0;
>  }
>  
> 
> 
> ------------------------------------------------------------------------
> 
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