сб, 11 нояб. 2023 г., 13:05 Zdravko Ćirić <zdravkociri...@gmail.com>:
> Hello all, > > I'm trying to combine an alternating fields interlaced video stream from an > UVC video device. The device is an analog (CVBS) to digital converter that > supports Interlaced video through usage of the FID flag in the UVC data > headers. USB Video Class documentation explanation "One field per sample: > Each sample contains only one field and the FID bit is used to indicate > whether a given video sample contains a top field or a bottom field". > Stream frame size is 720x288pix at 50fps and the output video should be > "combed" and result in a 720x576pix video at 25fps. > > I tried weave and tinterlace filters but it works on random as ffmpeg seems > to miss the data regarding the field polarity. > > Could ffmpeg make use of this flag so that i can join two fields in one > frame in correct order? > good question. I looked into source and there seems to be some support for reading interlace and esp. top field first signal in there? if (fmt.fmt.pix.field == V4L2_FIELD_INTERLACED) { av_log(ctx, AV_LOG_DEBUG, "The V4L2 driver is using the interlaced mode\n"); s->interlaced = 1; but also static int first_field(const struct video_data *s) { int res; v4l2_std_id std; res = v4l2_ioctl(s->fd, VIDIOC_G_STD, &std); if (res < 0) return 0; if (std & V4L2_STD_NTSC) return 0; return 1; } does this mean this function always return "not a top field" if format == NTSC? due to this chunk below .. ===== if ((res = mmap_init(ctx)) || (res = mmap_start(ctx)) < 0) goto fail; s->top_field_first = first_field(s); st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO; st->codecpar->codec_id = codec_id; ===== src is ffmpeg-6.1/libavdevice/v4l2.c > > > Thank you in advance > _______________________________________________ > ffmpeg-user mailing list > ffmpeg-user@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe". > _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".