[FFmpeg-devel] [PATCH] libavformat/rot: added rot pcm header support

[FFmpeg-devel] [PATCH] libavformat/rot: added rot pcm header support

[9mmilly via ffmpeg-devel]

implemented rot muxer and demuxer
---
 configure                |   2 +
 libavformat/Makefile     |   2 +
 libavformat/allformats.c |   2 +
 libavformat/rot.c        | 230 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 236 insertions(+)
 create mode 100644 libavformat/rot.c

diff --git a/configure b/configure
index 01edfacacc..360cb38431 100755
--- a/configure
+++ b/configure
@@ -3875,6 +3875,8 @@ ogg_demuxer_select="dirac_parse"
 ogv_muxer_select="ogg_muxer"
 opus_muxer_select="ogg_muxer"
 psp_muxer_select="mov_muxer"
+rot_demuxer_select="pcm"
+rot_muxer_select=""
 rtp_demuxer_select="sdp_demuxer"
 rtp_muxer_select="iso_writer"
 rtp_mpegts_muxer_select="mpegts_muxer rtp_muxer"
diff --git a/libavformat/Makefile b/libavformat/Makefile
index 5fd3f7252a..c7fbaa1c33 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -521,6 +521,8 @@ OBJS-$(CONFIG_RM_DEMUXER)                += rmdec.o rm.o rmsipr.o
 OBJS-$(CONFIG_RM_MUXER)                  += rmenc.o rm.o
 OBJS-$(CONFIG_ROQ_DEMUXER)               += idroqdec.o
 OBJS-$(CONFIG_ROQ_MUXER)                 += idroqenc.o rawenc.o
+OBJS-$(CONFIG_ROT_DEMUXER)               += rot.o pcm.o
+OBJS-$(CONFIG_ROT_MUXER)                 += rot.o
 OBJS-$(CONFIG_RSD_DEMUXER)               += rsd.o
 OBJS-$(CONFIG_RPL_DEMUXER)               += rpl.o
 OBJS-$(CONFIG_RSO_DEMUXER)               += rsodec.o rso.o pcm.o
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index 6ec361fb7b..e730f88568 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -407,6 +407,8 @@ extern const FFInputFormat  ff_rm_demuxer;
 extern const FFOutputFormat ff_rm_muxer;
 extern const FFInputFormat  ff_roq_demuxer;
 extern const FFOutputFormat ff_roq_muxer;
+extern const FFInputFormat ff_rot_demuxer;
+extern const FFOutputFormat ff_rot_muxer;
 extern const FFInputFormat  ff_rpl_demuxer;
 extern const FFInputFormat  ff_rsd_demuxer;
 extern const FFInputFormat  ff_rso_demuxer;
diff --git a/libavformat/rot.c b/libavformat/rot.c
new file mode 100644
index 0000000000..520f038f8b
--- /dev/null
+++ b/libavformat/rot.c
@@ -0,0 +1,230 @@
+/*
+* Copyright (c) 2014 9mmilly
+*
+* This file is part of FFmpeg.
+*
+* Permission to use, copy, modify, and/or distribute this software for any
+* purpose with or without fee is hereby granted, provided that the above
+* copyright notice and this permission notice appear in all copies.
+*
+* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#include <stdint.h>
+#include <string.h>
+
+#include "avformat.h"
+#include "demux.h"
+#include "internal.h"
+#include "libavcodec/codec_id.h"
+#include "mux.h"
+#include "pcm.h"
+#include "rawenc.h"
+
+#define ROT_IDENTIFIER "frot"
+
+typedef enum {
+    ROT_FORMAT_S8,
+    ROT_FORMAT_S16,
+    ROT_FORMAT_S24,
+    ROT_FORMAT_S32,
+    ROT_FORMAT_FLOAT,
+    ROT_FORMAT_DOUBLE
+} rot_format;
+
+/* demuxer */
+
+static int rot_probe(const AVProbeData *probe) {
+    if (probe->buf_size <= 32)
+        return 0;
+
+    if (probe->buf_size >= 36) {
+        if (memcmp(probe->buf, ROT_IDENTIFIER, 4) == 0)
+            return AVPROBE_SCORE_MAX;
+    }
+    return 0;
+}
+
+static int rot_read_header(AVFormatContext *context) {
+    uint8_t header_buffer[8];
+
+    if (avio_read(context->pb, header_buffer, sizeof(header_buffer)) != 8)
+        return AVERROR_INVALIDDATA;
+
+    uint16_t sample_rate;
+    memcpy(&sample_rate, (header_buffer + 4), 2);
+
+    uint8_t channels;
+    memcpy(&channels, (header_buffer + 6), 1);
+
+    uint8_t format;
+    memcpy(&format, (header_buffer + 7), 1);
+
+    if (sample_rate <= 0 || channels <= 0)
+        return AVERROR_INVALIDDATA;
+
+    AVStream *stream = avformat_new_stream(context, NULL);
+    if (!stream) {
+        av_log(stream, AV_LOG_ERROR, "invalid audio parameters\n");
+        return AVERROR(ENOMEM);
+    }
+
+    stream->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
+    stream->codecpar->ch_layout.nb_channels = channels;
+    stream->codecpar->sample_rate = sample_rate;
+
+    switch (format) {
+    case ROT_FORMAT_S8:
+        stream->codecpar->codec_id = AV_CODEC_ID_PCM_S8;
+        stream->codecpar->bits_per_coded_sample = 8;
+        stream->codecpar->block_align = 8 * channels / 8;
+        stream->codecpar->bit_rate = (int64_t)sample_rate * channels * 8;
+        break;
+
+    case ROT_FORMAT_S16:
+        stream->codecpar->codec_id = AV_CODEC_ID_PCM_S16LE;
+        stream->codecpar->bits_per_coded_sample = 16;
+        stream->codecpar->block_align = 16 * channels / 8;
+        stream->codecpar->bit_rate = (int64_t)sample_rate * channels * 16;
+        break;
+
+    case ROT_FORMAT_S24:
+        stream->codecpar->codec_id = AV_CODEC_ID_PCM_S24LE;
+        stream->codecpar->bits_per_coded_sample = 24;
+        stream->codecpar->block_align = 24 * channels / 8;
+        stream->codecpar->bit_rate = (int64_t)sample_rate * channels * 24;
+        break;
+
+    case ROT_FORMAT_S32:
+        stream->codecpar->codec_id = AV_CODEC_ID_PCM_S32LE;
+        stream->codecpar->bits_per_coded_sample = 32;
+        stream->codecpar->block_align = 32 * channels / 8;
+        stream->codecpar->bit_rate = (int64_t)sample_rate * channels * 32;
+        break;
+
+    case ROT_FORMAT_FLOAT:
+        stream->codecpar->codec_id = AV_CODEC_ID_PCM_F32LE;
+        stream->codecpar->bits_per_coded_sample = 32;
+        stream->codecpar->block_align = 32 * channels / 8;
+        stream->codecpar->bit_rate = (int64_t)sample_rate * channels * 32;
+        break;
+
+    case ROT_FORMAT_DOUBLE:
+        stream->codecpar->codec_id = AV_CODEC_ID_PCM_F64LE;
+        stream->codecpar->bits_per_coded_sample = 64;
+        stream->codecpar->block_align = 64 * channels / 8;
+        stream->codecpar->bit_rate = (int64_t)sample_rate * channels * 64;
+        break;
+
+    default:
+        return AVERROR_INVALIDDATA;
+    }
+    avpriv_set_pts_info(stream, 64, 1, sample_rate);
+
+    return 0;
+}
+
+const FFInputFormat ff_rot_demuxer = {
+    .p.name = "rot",
+    .p.long_name = NULL_IF_CONFIG_SMALL("rot pcm header"),
+    .priv_data_size = 0,
+    .p.extensions = "rot",
+    .read_probe = rot_probe,
+    .read_header = rot_read_header,
+    .read_packet = ff_pcm_read_packet};
+
+/* muxer */
+
+static int rot_write_header(AVFormatContext *context) {
+
+    const FFOutputFormat *ofmt = ffofmt(context->oformat);
+    av_log(context, AV_LOG_INFO, "flags_internal: 0x%x\n",
+           ofmt->flags_internal);
+
+    if (context->nb_streams <= 0)
+        return AVERROR(EINVAL);
+
+    AVStream *stream = context->streams[0];
+    if (stream == NULL)
+        return AVERROR(EINVAL);
+
+    uint8_t header_buffer[8];
+    uint16_t sample_rate = stream->codecpar->sample_rate;
+    uint8_t channels = stream->codecpar->ch_layout.nb_channels;
+
+    if (sample_rate <= 0 || channels <= 0)
+        return AVERROR(EINVAL);
+
+    uint8_t format;
+    switch (stream->codecpar->codec_id) {
+    case AV_CODEC_ID_PCM_S8:
+        format = ROT_FORMAT_S8;
+        break;
+
+    case AV_CODEC_ID_PCM_S16LE:
+        format = ROT_FORMAT_S16;
+        break;
+
+    case AV_CODEC_ID_PCM_S24LE:
+        format = ROT_FORMAT_S24;
+        break;
+
+    case AV_CODEC_ID_PCM_S32LE:
+        format = ROT_FORMAT_S32;
+        break;
+
+    case AV_CODEC_ID_PCM_F32LE:
+        format = ROT_FORMAT_FLOAT;
+        break;
+
+    case AV_CODEC_ID_PCM_F64LE:
+        format = ROT_FORMAT_DOUBLE;
+        break;
+    default:
+        return AVERROR(EINVAL);
+    }
+
+    memcpy(header_buffer, ROT_IDENTIFIER, 4);
+    memcpy(header_buffer + 4, &sample_rate, 2);
+    memcpy(header_buffer + 6, &channels, 1);
+    memcpy(header_buffer + 7, &format, 1);
+
+    avio_write(context->pb, header_buffer, sizeof(header_buffer));
+    return 0;
+}
+
+static int rot_write_packet(AVFormatContext *context, AVPacket *packet) {
+    avio_write(context->pb, packet->data, packet->size);
+    return 0;
+}
+
+static int rot_query_codec(enum AVCodecID codec_id, int std_compliance) {
+    switch (codec_id) {
+    case AV_CODEC_ID_PCM_S8:
+    case AV_CODEC_ID_PCM_S16LE:
+    case AV_CODEC_ID_PCM_S24LE:
+    case AV_CODEC_ID_PCM_S32LE:
+    case AV_CODEC_ID_PCM_F32LE:
+    case AV_CODEC_ID_PCM_F64LE:
+        return 1;
+    default:
+        return 0;
+    }
+}
+
+const FFOutputFormat ff_rot_muxer = {
+    .p.name = "rot",
+    .p.long_name = NULL_IF_CONFIG_SMALL("rot pcm header"),
+    .priv_data_size = 0,
+    .p.extensions = "rot",
+    .p.audio_codec = AV_CODEC_ID_PCM_S16LE,
+    .query_codec = rot_query_codec,
+    .write_header = rot_write_header,
+    .write_packet = rot_write_packet,
+};
-- 
2.51.2

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[FFmpeg-devel] Re: [PATCH] libavformat/rot: added rot pcm header support

[Rémi Denis-Courmont via ffmpeg-devel]

Le perjantaina 23. tammikuuta 2026, 14.35.29 Itä-Euroopan normaaliaika 9mmilly 
via ffmpeg-devel a écrit :
> implemented rot muxer and demuxer

Please resubmit via code.ffmpeg.org. Also this could use some background 
information on what the format is and how it's _actually_ used.

We can't just add every toy file format that someone might have invented.

-- 
Rémi Denis-Courmont
https://www.remlab.net/



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[FFmpeg-devel] Re: [PATCH] libavformat/rot: added rot pcm header support

[Michael Niedermayer via ffmpeg-devel]

[-- Attachment #1.1: Type: text/plain, Size: 5790 bytes --]

Hi

On Fri, Jan 23, 2026 at 01:35:29PM +0100, 9mmilly via ffmpeg-devel wrote:
[...]
> diff --git a/libavformat/rot.c b/libavformat/rot.c
> new file mode 100644
> index 0000000000..520f038f8b
> --- /dev/null
> +++ b/libavformat/rot.c
> @@ -0,0 +1,230 @@
> +/*
> +* Copyright (c) 2014 9mmilly
> +*
> +* This file is part of FFmpeg.
> +*
> +* Permission to use, copy, modify, and/or distribute this software for any
> +* purpose with or without fee is hereby granted, provided that the above
> +* copyright notice and this permission notice appear in all copies.
> +*
> +* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
> +* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
> +* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
> +* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
> +* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
> +* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
> +* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
> +*/
> +
> +#include <stdint.h>
> +#include <string.h>
> +
> +#include "avformat.h"
> +#include "demux.h"
> +#include "internal.h"
> +#include "libavcodec/codec_id.h"
> +#include "mux.h"
> +#include "pcm.h"
> +#include "rawenc.h"
> +
> +#define ROT_IDENTIFIER "frot"
> +
> +typedef enum {
> +    ROT_FORMAT_S8,
> +    ROT_FORMAT_S16,
> +    ROT_FORMAT_S24,
> +    ROT_FORMAT_S32,
> +    ROT_FORMAT_FLOAT,
> +    ROT_FORMAT_DOUBLE
> +} rot_format;
> +
> +/* demuxer */
> +

> +static int rot_probe(const AVProbeData *probe) {
> +    if (probe->buf_size <= 32)
> +        return 0;
> +
> +    if (probe->buf_size >= 36) {
> +        if (memcmp(probe->buf, ROT_IDENTIFIER, 4) == 0)
> +            return AVPROBE_SCORE_MAX;
> +    }
> +    return 0;
> +}

the probe->buf_size <= 32 block is redundant



> +
> +static int rot_read_header(AVFormatContext *context) {
> +    uint8_t header_buffer[8];
> +
> +    if (avio_read(context->pb, header_buffer, sizeof(header_buffer)) != 8)
> +        return AVERROR_INVALIDDATA;
> +

> +    uint16_t sample_rate;
> +    memcpy(&sample_rate, (header_buffer + 4), 2);

will fail on big endian


> +
> +    uint8_t channels;
> +    memcpy(&channels, (header_buffer + 6), 1);
> +
> +    uint8_t format;
> +    memcpy(&format, (header_buffer + 7), 1);
> +
> +    if (sample_rate <= 0 || channels <= 0)
> +        return AVERROR_INVALIDDATA;
> +
> +    AVStream *stream = avformat_new_stream(context, NULL);
> +    if (!stream) {
> +        av_log(stream, AV_LOG_ERROR, "invalid audio parameters\n");
> +        return AVERROR(ENOMEM);
> +    }
> +
> +    stream->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
> +    stream->codecpar->ch_layout.nb_channels = channels;
> +    stream->codecpar->sample_rate = sample_rate;
> +

> +    switch (format) {
> +    case ROT_FORMAT_S8:
> +        stream->codecpar->codec_id = AV_CODEC_ID_PCM_S8;
> +        stream->codecpar->bits_per_coded_sample = 8;
> +        stream->codecpar->block_align = 8 * channels / 8;
> +        stream->codecpar->bit_rate = (int64_t)sample_rate * channels * 8;
> +        break;
> +
> +    case ROT_FORMAT_S16:
> +        stream->codecpar->codec_id = AV_CODEC_ID_PCM_S16LE;
> +        stream->codecpar->bits_per_coded_sample = 16;
> +        stream->codecpar->block_align = 16 * channels / 8;
> +        stream->codecpar->bit_rate = (int64_t)sample_rate * channels * 16;
> +        break;
> +
> +    case ROT_FORMAT_S24:
> +        stream->codecpar->codec_id = AV_CODEC_ID_PCM_S24LE;
> +        stream->codecpar->bits_per_coded_sample = 24;
> +        stream->codecpar->block_align = 24 * channels / 8;
> +        stream->codecpar->bit_rate = (int64_t)sample_rate * channels * 24;
> +        break;
> +
> +    case ROT_FORMAT_S32:
> +        stream->codecpar->codec_id = AV_CODEC_ID_PCM_S32LE;
> +        stream->codecpar->bits_per_coded_sample = 32;
> +        stream->codecpar->block_align = 32 * channels / 8;
> +        stream->codecpar->bit_rate = (int64_t)sample_rate * channels * 32;
> +        break;
> +
> +    case ROT_FORMAT_FLOAT:
> +        stream->codecpar->codec_id = AV_CODEC_ID_PCM_F32LE;
> +        stream->codecpar->bits_per_coded_sample = 32;
> +        stream->codecpar->block_align = 32 * channels / 8;
> +        stream->codecpar->bit_rate = (int64_t)sample_rate * channels * 32;
> +        break;
> +
> +    case ROT_FORMAT_DOUBLE:
> +        stream->codecpar->codec_id = AV_CODEC_ID_PCM_F64LE;
> +        stream->codecpar->bits_per_coded_sample = 64;
> +        stream->codecpar->block_align = 64 * channels / 8;
> +        stream->codecpar->bit_rate = (int64_t)sample_rate * channels * 64;
> +        break;

the computation of block_align and bit_rate can be factored out using
bits_per_coded_sample


> +
> +    default:
> +        return AVERROR_INVALIDDATA;
> +    }
> +    avpriv_set_pts_info(stream, 64, 1, sample_rate);
> +
> +    return 0;
> +}
> +
> +const FFInputFormat ff_rot_demuxer = {
> +    .p.name = "rot",
> +    .p.long_name = NULL_IF_CONFIG_SMALL("rot pcm header"),
> +    .priv_data_size = 0,
> +    .p.extensions = "rot",
> +    .read_probe = rot_probe,
> +    .read_header = rot_read_header,
> +    .read_packet = ff_pcm_read_packet};
> +

> +/* muxer */
> +
> +static int rot_write_header(AVFormatContext *context) {

its probably cleaner to have this in a seperate file

thx

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Those who are too smart to engage in politics are punished by being
governed by those who are dumber. -- Plato 

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