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avformat/iamf_writer: add support for expanded channel layouts

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Defined in Immersive Audio Model and Formats 1.1.0, sections 3.6.2 and 3.7.3

Signed-off-by: James Almer <jamrial@gmail.com>
This commit is contained in:
James Almer 2024-12-10 10:56:14 -03:00
parent d255f90242
commit cc9843dc33
1 changed files with 17 additions and 4 deletions
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21
libavformat/iamf_writer.c
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@ -240,8 +240,13 @@ int ff_iamf_add_audio_element(IAMFContext *iamf, const AVStreamGroup *stg, void
break;
if (j >= FF_ARRAY_ELEMS(ff_iamf_scalable_ch_layouts)) {
av_log(log_ctx, AV_LOG_ERROR, "Unsupported channel layout in stream group #%d\n", i);
return AVERROR(EINVAL);
for (j = 0; j < FF_ARRAY_ELEMS(ff_iamf_expanded_scalable_ch_layouts); j++)
if (!av_channel_layout_compare(&layer->ch_layout, &ff_iamf_expanded_scalable_ch_layouts[j]))
break;
if (j >= FF_ARRAY_ELEMS(ff_iamf_expanded_scalable_ch_layouts)) {
av_log(log_ctx, AV_LOG_ERROR, "Unsupported channel layout in stream group #%d\n", i);
return AVERROR(EINVAL);
}
}
}
@ -539,13 +544,19 @@ static int scalable_channel_layout_config(const IAMFAudioElement *audio_element,
avio_write(dyn_bc, header, put_bytes_count(&pb, 1));
for (int i = 0; i < element->nb_layers; i++) {
const AVIAMFLayer *layer = element->layers[i];
int layout;
int layout, expanded_layout = -1;
for (layout = 0; layout < FF_ARRAY_ELEMS(ff_iamf_scalable_ch_layouts); layout++) {
if (!av_channel_layout_compare(&layer->ch_layout, &ff_iamf_scalable_ch_layouts[layout]))
break;
}
if (layout >= FF_ARRAY_ELEMS(ff_iamf_scalable_ch_layouts))
for (expanded_layout = 0; expanded_layout < FF_ARRAY_ELEMS(ff_iamf_scalable_ch_layouts); expanded_layout++) {
if (!av_channel_layout_compare(&layer->ch_layout, &ff_iamf_expanded_scalable_ch_layouts[expanded_layout]))
break;
}
av_assert0(expanded_layout > 0 || layout < FF_ARRAY_ELEMS(ff_iamf_scalable_ch_layouts));
init_put_bits(&pb, header, sizeof(header));
put_bits(&pb, 4, layout);
put_bits(&pb, 4, expanded_layout >= 0 ? 15 : layout);
put_bits(&pb, 1, !!layer->output_gain_flags);
put_bits(&pb, 1, !!(layer->flags & AV_IAMF_LAYER_FLAG_RECON_GAIN));
put_bits(&pb, 2, 0); // reserved
@ -556,6 +567,8 @@ static int scalable_channel_layout_config(const IAMFAudioElement *audio_element,
put_bits(&pb, 2, 0);
put_bits(&pb, 16, rescale_rational(layer->output_gain, 1 << 8));
}
if (expanded_layout >= 0)
put_bits(&pb, 8, expanded_layout);
flush_put_bits(&pb);
avio_write(dyn_bc, header, put_bytes_count(&pb, 1));
}