Hi,
On Sun, 27 Aug 2017 21:41:06 +0200
Jorge Ramirez <jorge.ramirez-ortiz at linaro.org> wrote:
> On 08/27/2017 09:09 PM, Jorge Ramirez wrote:
> > On 08/25/2017 05:35 PM, wm4 wrote:
> >>> +static int buffer_ops_v4l2buf_to_avframe(AVFrame *frame,
> >>> V4L2Buffer *avbuf) +{
> >>> + int i, ret;
> >>> +
> >>> + av_frame_unref(frame);
> >>> +
> >>> + /* 1. get references to the actual data */
> >>> + for (i = 0; i < avbuf->num_planes; i++) {
> >>> + ret = avbuf->ops.buf_to_bufref(avbuf, i, &frame->buf[i]);
> >>> + if (ret)
> >>> + return ret;
> >>> +
> >>> + frame->linesize[i] = avbuf->bytesperline[i];
> >>> + frame->data[i] = frame->buf[i]->data;
> >>> + }
> >>> +
> >>> + /* 1.1 fixup special cases */
> >>> + switch (avbuf->context->av_pix_fmt) {
> >>> + case AV_PIX_FMT_NV12:
> >>> + if (avbuf->num_planes > 1)
> >>> + break;
> >>> + frame->linesize[1] = avbuf->bytesperline[0];
> >>> + frame->data[1] = frame->buf[0]->data +
> >>> avbuf->bytesperline[0] * avbuf->context->format.fmt.pix_mp.height;
> >>> + break;
> >>> + default:
> >>> + break;
> >>> + }
> >>> +
> >>> + /* 2. get frame information */
> >>> + frame->key_frame = !!(avbuf->buf.flags &
> >>> V4L2_BUF_FLAG_KEYFRAME);
> >>> + frame->format = avbuf->context->av_pix_fmt;
> >>> +
> >>> + /* these values are updated also during re-init in
> >>> process_video_event */
> >>> + frame->height = avbuf->context->height;
> >>> + frame->width = avbuf->context->width;
> >>> + frame->pts = get_pts(avbuf);
> >>> +
> >>> + /* 3. report errors upstream */
> >>> + if (avbuf->buf.flags & V4L2_BUF_FLAG_ERROR) {
> >>> + av_log(avbuf->context->log_ctx, AV_LOG_ERROR, "%s:
> >>> driver decode error\n", avbuf->context->name);
> >>> + frame->decode_error_flags |=
> >>> FF_DECODE_ERROR_INVALID_BITSTREAM;
> >>> + }
> >>> +
> >>> + return 0;
> >>> +}
> >> This function seems to lack setting typically required metadata
> >> like colorspace.
> >>
> >
> > ok I will retrieve the colorspace from the v4l2 format structure
> > and set it in the frame.
>
> um, I dont see a 1:1 mapping between the colorspaces reported from
> v4l2 and what ffmpeg expects (I am also not a subject matter expert
> on this :( ).
>
> Could I get some guidance on the translation table below please?
> btw in my simple tests - ffplay decoded vp8, vp9, mpeg4, mpeg2, h263,
> h264 and hevc I didnt need this field so I am not sure if I am
> getting it right.
I don't think it will affect decoding, but the image will be something like too pale if it's set wrongly
> static inline enum AVColorSpace get_colorspace(V4L2Buffer *buf)
> {
> enum v4l2_colorspace cs;
>
> cs = V4L2_TYPE_IS_MULTIPLANAR(buf->context->type) ?
> buf->context->format.fmt.pix_mp.colorspace :
> buf->context->format.fmt.pix.colorspace;
>
> /* */
> switch (cs) {
> case V4L2_COLORSPACE_SMPTE170M: return AVCOL_SPC_SMPTE170M;
> case V4L2_COLORSPACE_SMPTE240M: return AVCOL_SPC_SMPTE240M;
> case V4L2_COLORSPACE_470_SYSTEM_BG: return AVCOL_SPC_BT470BG;
> case V4L2_COLORSPACE_BT2020: return AVCOL_SPC_BT2020_CL;
> case V4L2_COLORSPACE_REC709: return AVCOL_SPC_BT709;
> case V4L2_COLORSPACE_ADOBERGB:
> case V4L2_COLORSPACE_SRGB:
> case V4L2_COLORSPACE_DCI_P3:
> case V4L2_COLORSPACE_JPEG:
> case V4L2_COLORSPACE_RAW:
> default:
> return AVCOL_SPC_RGB;
> }
FWIW, here is the conversion I had been using in other projects:
switch(f->colorspace)
{
case V4L2_COLORSPACE_SRGB:
return AVCOL_SPC_RGB;
case V4L2_COLORSPACE_REC709:
return AVCOL_SPC_BT709;
case V4L2_COLORSPACE_470_SYSTEM_M:
return AVCOL_SPC_FCC;
case V4L2_COLORSPACE_470_SYSTEM_BG:
return AVCOL_SPC_BT470BG;
case V4L2_COLORSPACE_SMPTE170M:
return AVCOL_SPC_SMPTE170M;
case V4L2_COLORSPACE_SMPTE240M:
return AVCOL_SPC_SMPTE240M;
case V4L2_COLORSPACE_BT2020:
if(f->ycbcr_enc == V4L2_YCBCR_ENC_BT2020_CONST_LUM)
return AVCOL_SPC_BT2020_CL;
return AVCOL_SPC_BT2020_NCL;
default: return AVCOL_SPC_UNSPECIFIED;
}
you'd likely need AVCOL_PRI*:
switch(f->ycbcr_enc)
{
case V4L2_YCBCR_ENC_XV709:
case V4L2_YCBCR_ENC_709 :
return AVCOL_PRI_BT709;
case V4L2_YCBCR_ENC_XV601:
case V4L2_YCBCR_ENC_601:
return AVCOL_PRI_BT470M;
default: break;
}
switch(f->colorspace)
{
case V4L2_COLORSPACE_470_SYSTEM_BG:
return AVCOL_PRI_BT470BG;
case V4L2_COLORSPACE_SMPTE170M:
return AVCOL_PRI_SMPTE170M;
case V4L2_COLORSPACE_SMPTE240M:
return AVCOL_PRI_SMPTE240M;
case V4L2_COLORSPACE_BT2020:
return AVCOL_PRI_BT2020;
default: break;
}
return AVCOL_PRI_UNSPECIFIED;
AVCOL_TRC*:
switch(f->xfer_func)
{
case V4L2_XFER_FUNC_709:
switch(f->bit_depth)
{
case 10: return AVCOL_TRC_BT2020_10;
case 12: return AVCOL_TRC_BT2020_12;
default: break;
}
return AVCOL_TRC_BT709;
case V4L2_XFER_FUNC_SRGB:
return AVCOL_TRC_IEC61966_2_1;
default: break;
}
switch(f->colorspace)
{
case V4L2_COLORSPACE_470_SYSTEM_M:
return AVCOL_TRC_GAMMA22;
case V4L2_COLORSPACE_470_SYSTEM_BG:
return AVCOL_TRC_GAMMA28;
case V4L2_COLORSPACE_SMPTE170M:
return AVCOL_TRC_SMPTE170M;
case V4L2_COLORSPACE_SMPTE240M:
return AVCOL_TRC_SMPTE240M;
default: break;
}
switch(f->ycbcr_enc)
{
case V4L2_YCBCR_ENC_XV709:
case V4L2_YCBCR_ENC_XV601:
return AVCOL_TRC_BT1361_ECG;
default: break;
}
return AVCOL_TRC_UNSPECIFIED;
AVCOL_RANGE*:
switch(f->quantization)
{
case V4L2_QUANTIZATION_LIM_RANGE:
return AVCOL_RANGE_MPEG;
case V4L2_QUANTIZATION_FULL_RANGE:
return AVCOL_RANGE_JPEG;
default: break;
}
return AVCOL_RANGE_UNSPECIFIED;
Feel free to re-use, point and/or fix bugs here (it's been long since I wrote this and I don't think I've ever visually checked all the possibilities).
This might also be useful for the V4L2 output and capture drivers in lavd.
Bests,
Alexis.