bitstream_put_ui(bs, 1, 1); /* colour_description_present_flag */
{
bitstream_put_ui(bs, 1, 8); /* colour_primaries (1 = BT.709) */
- bitstream_put_ui(bs, 1, 8); /* transfer_characteristics (1 = BT.709) */
+ bitstream_put_ui(bs, 2, 8); /* transfer_characteristics (2 = unspecified, since we use sRGB) */
bitstream_put_ui(bs, 6, 8); /* matrix_coefficients (6 = BT.601/SMPTE 170M) */
}
}
// Note that the H.264 stream also contains this information and depending on the
// mux, this might simply get ignored. See sps_rbsp().
avstream_video->codec->color_primaries = AVCOL_PRI_BT709; // RGB colorspace (inout_format.color_space).
- avstream_video->codec->color_trc = AVCOL_TRC_BT709; // Gamma curve (inout_format.gamma_curve).
+ avstream_video->codec->color_trc = AVCOL_TRC_UNSPECIFIED; // Gamma curve (inout_format.gamma_curve).
avstream_video->codec->colorspace = AVCOL_SPC_SMPTE170M; // YUV colorspace (output_ycbcr_format.luma_coefficients).
avstream_video->codec->color_range = AVCOL_RANGE_MPEG; // Full vs. limited range (output_ycbcr_format.full_range).
avstream_video->codec->chroma_sample_location = AVCHROMA_LOC_LEFT; // Chroma sample location. See chroma_offset_0[] in Mixer::subsample_chroma().
ImageFormat inout_format;
inout_format.color_space = COLORSPACE_REC_709;
- // Gamma curve depends on the input signal, and we don't really get any
- // indications. A camera would be expected to do Rec. 709, but
- // I haven't checked if any do in practice. However, computers _do_ output
- // in sRGB gamma (ie., they don't convert from sRGB to Rec. 709), and
- // I wouldn't really be surprised if most non-professional cameras do, too.
- // So we pick sRGB as the least evil here.
+ // Output gamma is tricky. We should output Rec. 709 for TV, except that
+ // we expect to run with web players and others that don't really care and
+ // just output with no conversion. So that means we'll need to output sRGB,
+ // even though H.264 has no setting for that (we use “unspecified”).
inout_format.gamma_curve = GAMMA_sRGB;
if (is_main_chain) {
{
ImageFormat inout_format;
inout_format.color_space = COLORSPACE_sRGB;
+
+ // Gamma curve depends on the input signal, and we don't really get any
+ // indications. A camera would be expected to do Rec. 709, but
+ // I haven't checked if any do in practice. However, computers _do_ output
+ // in sRGB gamma (ie., they don't convert from sRGB to Rec. 709), and
+ // I wouldn't really be surprised if most non-professional cameras do, too.
+ // So we pick sRGB as the least evil here.
inout_format.gamma_curve = GAMMA_sRGB;
// The Blackmagic driver docs claim that the device outputs Y'CbCr