PR #21330 opened by James Almer (jamrial) URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21330 Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21330.patch
>From af60dd84194b8ae6a3c1bf4ee474bc06bcf7023d Mon Sep 17 00:00:00 2001 From: James Almer <[email protected]> Date: Sat, 27 Dec 2025 17:08:30 -0300 Subject: [PATCH 1/3] avformat/iamf_parse: fix setting denominator in AVIAMFLayer.demixing_matrix The format of demixing_matrix is Q15 fixed point values. Signed-off-by: James Almer <[email protected]> (cherry picked from commit 03a981445ee89a567e5a98ec88cbbbb8d3e3af72) --- libavformat/iamf_parse.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavformat/iamf_parse.c b/libavformat/iamf_parse.c index 597d800be0..65dbfa0d1e 100644 --- a/libavformat/iamf_parse.c +++ b/libavformat/iamf_parse.c @@ -555,7 +555,7 @@ static int ambisonics_config(void *s, AVIOContext *pb, return AVERROR(ENOMEM); for (int i = 0; i < demixing_matrix_size; i++) - layer->demixing_matrix[i] = av_make_q(sign_extend(avio_rb16(pb), 16), 1 << 8); + layer->demixing_matrix[i] = av_make_q(sign_extend(avio_rb16(pb), 16), 1 << 15); for (int i = 0; i < substream_count; i++) { IAMFSubStream *substream = &audio_element->substreams[i]; -- 2.49.1 >From 06fcee2e2605364bda5613ff28ef5d06e3dc0377 Mon Sep 17 00:00:00 2001 From: James Almer <[email protected]> Date: Sat, 27 Dec 2025 18:06:32 -0300 Subject: [PATCH 2/3] avformat/iamf_writer: fix writting some ambisonics fields in Audio Elements The fields are defined as 8 bit long unsigned ints. Fortunately, writing most sane values as leb is equivalent, which is why no tests are affected. Signed-off-by: James Almer <[email protected]> (cherry picked from commit 21ff60d2cf7dfe00400ffef6a8843736f4cf9a2f) --- libavformat/iamf_writer.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/libavformat/iamf_writer.c b/libavformat/iamf_writer.c index e9dd170380..4ad6521f31 100644 --- a/libavformat/iamf_writer.c +++ b/libavformat/iamf_writer.c @@ -662,8 +662,8 @@ static int ambisonics_config(const IAMFAudioElement *audio_element, const AVIAMFLayer *layer = element->layers[0]; ffio_write_leb(dyn_bc, 0); // ambisonics_mode - ffio_write_leb(dyn_bc, layer->ch_layout.nb_channels); // output_channel_count - ffio_write_leb(dyn_bc, audio_element->nb_substreams); // substream_count + avio_w8(dyn_bc, layer->ch_layout.nb_channels); // output_channel_count + avio_w8(dyn_bc, audio_element->nb_substreams); // substream_count if (layer->ch_layout.order == AV_CHANNEL_ORDER_AMBISONIC) for (int i = 0; i < layer->ch_layout.nb_channels; i++) -- 2.49.1 >From bfa334de42a5d81df2bcea67113acf718593aaf6 Mon Sep 17 00:00:00 2001 From: James Almer <[email protected]> Date: Sat, 27 Dec 2025 19:11:07 -0300 Subject: [PATCH 3/3] avformat/iamf_writer: check that stream count is consistent for ambisonic Audio Elements Signed-off-by: James Almer <[email protected]> (cherry picked from commit a0fc454871c116d5bd1bbec5138dfe3ffcb1f11d) --- libavformat/iamf_writer.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/libavformat/iamf_writer.c b/libavformat/iamf_writer.c index 4ad6521f31..c2de13b543 100644 --- a/libavformat/iamf_writer.c +++ b/libavformat/iamf_writer.c @@ -659,8 +659,12 @@ static int ambisonics_config(const IAMFAudioElement *audio_element, AVIOContext *dyn_bc) { const AVIAMFAudioElement *element = audio_element->celement; + const IAMFLayer *ilayer = &audio_element->layers[0]; const AVIAMFLayer *layer = element->layers[0]; + if (audio_element->nb_substreams != ilayer->substream_count) + return AVERROR(EINVAL); + ffio_write_leb(dyn_bc, 0); // ambisonics_mode avio_w8(dyn_bc, layer->ch_layout.nb_channels); // output_channel_count avio_w8(dyn_bc, audio_element->nb_substreams); // substream_count -- 2.49.1 _______________________________________________ ffmpeg-devel mailing list -- [email protected] To unsubscribe send an email to [email protected]
