mtmd : add support for Voxtral (#14862)

* mtmd : add support for Voxtral

* clean up

* fix python requirements

* add [BEGIN_AUDIO] token

* also support Devstral conversion

* add docs and tests

* fix regression for ultravox

* minor coding style improvement

* correct project activation fn

* Apply suggestions from code review

Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com>

---------

Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com>

.gitignore

@@ -82,6 +82,7 @@ models/*
 models-mnt
 !models/.editorconfig
 !models/ggml-vocab-*.gguf*
+!models/templates
 
 # Zig
 zig-out/

convert_hf_to_gguf.py

@@ -1900,6 +1900,7 @@ class StableLMModel(TextModel):
     "MixtralForCausalLM",
     "VLlama3ForCausalLM",
     "LlavaForConditionalGeneration",
+    "VoxtralForConditionalGeneration",
     "LlamaModel")
 class LlamaModel(TextModel):
     model_arch = gguf.MODEL_ARCH.LLAMA
@@ -1912,6 +1913,11 @@ class LlamaModel(TextModel):
             self.hparams["num_attention_heads"] = self.hparams.get("num_attention_heads", 32)
 
     def set_vocab(self):
+        path_tekken_json = self.dir_model / "tekken.json"
+        path_tokenizer_json = self.dir_model / "tokenizer.json"
+        if path_tekken_json.is_file() and not path_tokenizer_json.is_file():
+            return self.set_vocab_tekken()
+
         try:
             self._set_vocab_sentencepiece()
         except FileNotFoundError:
@@ -1944,6 +1950,52 @@ class LlamaModel(TextModel):
         if self.hparams.get("vocab_size", 32000) == 49152:
             self.gguf_writer.add_add_bos_token(False)
 
+    def set_vocab_tekken(self):
+        vocab = gguf.vocab.MistralVocab(self.dir_model)
+        self.gguf_writer.add_tokenizer_model(vocab.gguf_tokenizer_model)
+
+        tokens = []
+        scores = []
+        toktypes = []
+
+        for text, score, toktype in vocab.all_tokens():
+            tokens.append(text)
+            scores.append(score)
+            toktypes.append(toktype)
+
+        assert len(tokens) == vocab.vocab_size, (
+            f"token count ({len(tokens)}) != vocab size ({vocab.vocab_size})"
+        )
+
+        if vocab.tokenizer_type == gguf.vocab.MistralTokenizerType.tekken:
+            self.gguf_writer.add_tokenizer_pre("tekken")
+            self.gguf_writer.add_token_merges(
+                vocab.extract_vocab_merges_from_model()
+            )
+
+        logger.info(
+            f"Setting bos, eos, unk and pad token IDs to {vocab.bos_id}, {vocab.eos_id}, {vocab.unk_id}, {vocab.pad_id}."
+        )
+
+        self.gguf_writer.add_bos_token_id(vocab.bos_id)
+        self.gguf_writer.add_eos_token_id(vocab.eos_id)
+        self.gguf_writer.add_unk_token_id(vocab.unk_id)
+        self.gguf_writer.add_pad_token_id(vocab.pad_id)
+
+        self.gguf_writer.add_token_list(tokens)
+        self.gguf_writer.add_token_scores(scores)
+        self.gguf_writer.add_token_types(toktypes)
+        self.gguf_writer.add_vocab_size(vocab.vocab_size)
+
+        self.gguf_writer.add_add_bos_token(True)
+        self.gguf_writer.add_add_eos_token(False)
+
+        script_dir = Path(__file__).parent
+        template_path = script_dir / "models/templates/unsloth-mistral-Devstral-Small-2507.jinja"
+        with open(template_path, "r", encoding="utf-8") as f:
+            template = f.read()
+            self.gguf_writer.add_chat_template(template)
+
     def set_gguf_parameters(self):
         super().set_gguf_parameters()
         hparams = self.hparams
@@ -1971,12 +2023,13 @@ class LlamaModel(TextModel):
     def modify_tensors(self, data_torch: Tensor, name: str, bid: int | None) -> Iterable[tuple[str, Tensor]]:
         n_head = self.hparams["num_attention_heads"]
         n_kv_head = self.hparams.get("num_key_value_heads")
-        is_vision_tensor = "vision_tower" in name \
+        is_multimodal_tensor = "vision_tower" in name \
             or "vision_model" in name \
+            or "audio_tower" in name \
             or "model.connector" in name \
             or "multi_modal_projector" in name
 
-        if is_vision_tensor:
+        if is_multimodal_tensor:
             return [] # skip vision tensors
         elif self.hf_arch == "LlamaModel":
             name = "model." + name
@@ -7231,9 +7284,10 @@ class WhisperEncoderModel(MmprojModel):
 
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
-        self.hparams["hidden_size"] = self.hparams["d_model"]
+        if "hidden_size" not in self.hparams and "intermediate_size" not in self.hparams:
-        self.hparams["intermediate_size"] = self.hparams["encoder_ffn_dim"]
+            self.hparams["hidden_size"] = self.hparams["d_model"]
-        self.hparams["num_attention_heads"] = self.hparams["encoder_attention_heads"]
+            self.hparams["intermediate_size"] = self.hparams["encoder_ffn_dim"]
+            self.hparams["num_attention_heads"] = self.hparams["encoder_attention_heads"]
 
     def set_gguf_parameters(self):
         super().set_gguf_parameters()
@@ -7272,9 +7326,21 @@ class UltravoxWhisperEncoderModel(WhisperEncoderModel):
 
     def set_gguf_parameters(self):
         super().set_gguf_parameters()
+        self.gguf_writer.add_clip_projector_type(gguf.VisionProjectorType.ULTRAVOX)
         self.gguf_writer.add_audio_stack_factor(self.global_config["stack_factor"])
 
 
+@ModelBase.register("VoxtralForConditionalGeneration")
+class VoxtralWhisperEncoderModel(WhisperEncoderModel):
+    has_vision_encoder = False # no vision encoder
+    has_audio_encoder = True
+
+    def set_gguf_parameters(self):
+        super().set_gguf_parameters()
+        self.gguf_writer.add_clip_projector_type(gguf.VisionProjectorType.VOXTRAL)
+        self.gguf_writer.add_audio_stack_factor(4) # == intermediate_size // hidden_size
+
+
 @ModelBase.register("FalconH1ForCausalLM")
 class FalconH1Model(Mamba2Model):
     model_arch = gguf.MODEL_ARCH.FALCON_H1

docs/multimodal.md

@@ -97,6 +97,9 @@ NOTE: some models may require large context window, for example: `-c 8192`
 # Qwen2-Audio and SeaLLM-Audio
 # note: no pre-quantized GGUF this model, as they have very poor result
 # ref: https://github.com/ggml-org/llama.cpp/pull/13760
+
+# Mistral's Voxtral
+(tool_name) -hf ggml-org/Voxtral-Mini-3B-2507-GGUF
 ```
 
 **Mixed modalities**:

gguf-py/gguf/constants.py

@@ -2724,6 +2724,7 @@ class VisionProjectorType:
     INTERNVL = "internvl"
     QWEN2A = "qwen2a" # audio
     QWEN25O = "qwen2.5o" # omni
+    VOXTRAL = "voxtral"
 
 
 # Items here are (block size, type size)

gguf-py/gguf/vocab.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+from enum import Enum
 import re
 import logging
 import json
@@ -12,6 +13,25 @@ try:
 except ImportError:
     SentencePieceProcessor = None
 
+try:
+    from mistral_common.tokens.tokenizers.mistral import MistralTokenizer
+    from mistral_common.tokens.tokenizers.tekken import Tekkenizer
+    from mistral_common.tokens.tokenizers.utils import (
+        _filter_valid_tokenizer_files,
+    )
+    from mistral_common.tokens.tokenizers.sentencepiece import (
+        SentencePieceTokenizer,
+    )
+except ImportError:
+    _mistral_common_installed = False
+    MistralTokenizer = None
+    Tekkenizer = None
+    SentencePieceTokenizer = None
+    _filter_valid_tokenizer_files = None
+else:
+    _mistral_common_installed = True
+
+
 import gguf
 
 from .gguf_writer import GGUFWriter
@@ -592,3 +612,262 @@ class LlamaHfVocab(Vocab):
 
     def __repr__(self) -> str:
         return f"<LlamaHfVocab with {self.vocab_size_base} base tokens and {len(self.added_tokens_list)} added tokens>"
+
+
+class MistralTokenizerType(str, Enum):
+    spm = "spm"
+    tekken = "tekken"
+
+
+# Copied from Transformers (Apache 2.0)
+# https://github.com/huggingface/transformers/blob/main/src/transformers/convert_slow_tokenizer.py#L1544
+
+def bytes_to_unicode() -> dict[int, str]:
+    """
+    Returns list of utf-8 byte and a mapping to unicode strings. We specifically avoids mapping to whitespace/control
+    characters the bpe code barfs on.
+
+    The reversible bpe codes work on unicode strings. This means you need a large # of unicode characters in your vocab
+    if you want to avoid UNKs. When you're at something like a 10B token dataset you end up needing around 5K for
+    decent coverage. This is a significant percentage of your normal, say, 32K bpe vocab. To avoid that, we want lookup
+    tables between utf-8 bytes and unicode strings.
+    """
+    bs = (
+        list(range(ord("!"), ord("~") + 1))
+        + list(range(ord("¡"), ord("¬") + 1))
+        + list(range(ord("®"), ord("ÿ") + 1))
+    )
+    cs = bs[:]
+    n = 0
+    for b in range(2**8):
+        if b not in bs:
+            bs.append(b)
+            cs.append(2**8 + n)
+            n += 1
+    cs_str = [chr(n) for n in cs]
+    return dict(zip(bs, cs_str))
+
+
+class MistralVocab(Vocab):
+    tokenizer_model = "mistral"
+    name = "mistral"
+
+    added_tokens_dict: dict[str, int] = {}
+    added_tokens_list: list[str] = []
+
+    def __init__(self, base_path: Path):
+        if not _mistral_common_installed:
+            raise ImportError(
+                "To use MistralVocab, please install the `mistral-common` package. "
+                "You can install it with `pip install mistral-common`."
+            )
+        assert _filter_valid_tokenizer_files is not None, "mistral_common is not installed"
+        assert MistralTokenizer is not None, "mistral_common is not installed"
+        assert Tekkenizer is not None, "mistral_common is not installed"
+
+        logger.info(f"Loading Mistral tokenizer from {base_path}")
+
+        # Find the tokenizer files
+        all_files = [f.as_posix() for f in base_path.glob("**/*") if f.is_file()]
+        valid_tokenizer_files = _filter_valid_tokenizer_files(all_files)
+
+        if len(valid_tokenizer_files) == 0:
+            raise ValueError(f"No tokenizer file found in the directory: {base_path}")
+        # If there are multiple tokenizer files, we use tekken.json if it exists, otherwise the versioned one.
+        if len(valid_tokenizer_files) > 1:
+            if "tekken.json" in valid_tokenizer_files:
+                tokenizer_file = "tekken.json"
+            else:
+                tokenizer_file = sorted(valid_tokenizer_files)[-1]
+            logger.warning(
+                f"Multiple tokenizer files found in {base_path}. Using {tokenizer_file}"
+            )
+        else:
+            tokenizer_file = valid_tokenizer_files[0]
+
+        self.tokenizer = MistralTokenizer.from_file(
+            base_path / tokenizer_file
+        ).instruct_tokenizer.tokenizer
+        self.tokenizer_type = (
+            MistralTokenizerType.tekken
+            if isinstance(self.tokenizer, Tekkenizer)
+            else MistralTokenizerType.spm
+        )
+        self.vocab_size = self.tokenizer.n_words
+        self.fname_tokenizer = base_path / tokenizer_file
+        self._name = (
+            "mistral-" + self.tokenizer_type.value + "-" + self.tokenizer.version
+        )
+
+    @property
+    def tokenizer_name(self) -> str:
+        return self._name
+
+    @property
+    def gguf_tokenizer_model(self) -> str:
+        return "llama" if self.tokenizer_type == MistralTokenizerType.spm else "gpt2"
+
+    def _sentencepiece_tokens(self) -> Iterable[tuple[bytes, float, gguf.TokenType]]:
+        assert SentencePieceTokenizer is not None, "mistral_common is not installed"
+        assert isinstance(self.tokenizer, SentencePieceTokenizer), (
+            f"Expected SentencePieceTokenizer, got {type(self.tokenizer)}"
+        )
+
+        for i in range(self.tokenizer._model.vocab_size()):
+            piece = self.tokenizer._model.IdToPiece(i)
+            text = piece.encode("utf-8")
+            score: float = self.tokenizer._model.GetScore(i)
+
+            toktype = gguf.TokenType.NORMAL
+            if self.tokenizer._model.IsUnknown(i):
+                toktype = gguf.TokenType.UNKNOWN
+            if self.tokenizer._model.IsControl(i):
+                toktype = gguf.TokenType.CONTROL
+
+            if self.tokenizer._model.IsUnused(i):
+                toktype = gguf.TokenType.UNUSED
+            if self.tokenizer._model.IsByte(i):
+                toktype = gguf.TokenType.BYTE
+
+            yield text, score, toktype
+
+    def _tekken_tokens(self) -> Iterable[tuple[bytes, float, gguf.TokenType]]:
+        assert Tekkenizer is not None, "mistral_common is not installed"
+        assert isinstance(self.tokenizer, Tekkenizer), (
+            f"Expected Tekkenizer, got {type(self.tokenizer)}"
+        )
+
+        byte_encoder = bytes_to_unicode()
+        for token_id in range(self.tokenizer.num_special_tokens):
+            yield (
+                self.tokenizer.id_to_piece(token_id).encode("utf-8"),
+                0,
+                gguf.TokenType.CONTROL
+            )
+        for token in self.tokenizer._tekken_token2id_nospecial:
+            yield (
+                self.token_bytes_to_string(token, byte_encoder).encode("utf-8"),
+                0,
+                gguf.TokenType.NORMAL,
+            )
+
+    def get_token_id(self, token: str) -> int:
+        assert SentencePieceTokenizer is not None and Tekkenizer is not None, "mistral_common is not installed"
+        if self.tokenizer_type == MistralTokenizerType.spm:
+            assert isinstance(self.tokenizer, SentencePieceTokenizer)
+            return self.tokenizer._vocab.index(token)
+        elif self.tokenizer_type == MistralTokenizerType.tekken:
+            assert isinstance(self.tokenizer, Tekkenizer)
+            return (
+                self.tokenizer._vocab.index(token) + self.tokenizer.num_special_tokens
+            )
+        else:
+            raise ValueError(f"Unknown tokenizer type: {self.tokenizer_type}")
+
+    @property
+    def bos_id(self) -> int:
+        return self.tokenizer.bos_id
+
+    @property
+    def eos_id(self) -> int:
+        return self.tokenizer.eos_id
+
+    @property
+    def pad_id(self) -> int:
+        if self.tokenizer.pad_id == -1:
+            return self.eos_id
+        return self.tokenizer.pad_id
+
+    @property
+    def unk_id(self) -> int:
+        return self.tokenizer.unk_id
+
+    @property
+    def bos_token(self) -> str:
+        return self.tokenizer.id_to_piece(self.tokenizer.bos_id)
+
+    @property
+    def eos_token(self) -> str:
+        return self.tokenizer.id_to_piece(self.tokenizer.eos_id)
+
+    @property
+    def pad_token(self) -> str:
+        return self.tokenizer.id_to_piece(self.tokenizer.pad_id)
+
+    @property
+    def unk_token(self) -> str:
+        return self.tokenizer.id_to_piece(self.tokenizer.unk_id)
+
+    def all_tokens(self) -> Iterable[tuple[bytes, float, gguf.TokenType]]:
+        if self.tokenizer_type == MistralTokenizerType.spm:
+            yield from self._sentencepiece_tokens()
+
+        elif self.tokenizer_type == MistralTokenizerType.tekken:
+            yield from self._tekken_tokens()
+
+        else:
+            raise ValueError(f"Unknown tokenizer type: {self.tokenizer_type}")
+
+    @staticmethod
+    def token_bytes_to_string(b, byte_encoder):
+        return "".join([byte_encoder[ord(char)] for char in b.decode("latin-1")])
+
+    def extract_vocab_merges_from_model(self):
+        # Adapted from Transformers (Apache 2.0)
+        # https://github.com/huggingface/transformers/blob/main/src/transformers/convert_slow_tokenizer.py
+        assert Tekkenizer is not None and isinstance(self.tokenizer, Tekkenizer), (
+            f"Expected Tekkenizer, got {type(self.tokenizer)}"
+        )
+        mergeable_ranks = self.tokenizer._model._mergeable_ranks
+        token_bytes_map = {
+            rank: token_bytes for token_bytes, rank in mergeable_ranks.items()
+        }
+        merge_pairs = []
+
+        # Sort vocab by rank to ensure correct merge order
+        for i in range(256, self.vocab_size - self.tokenizer.num_special_tokens):
+            merged_token = token_bytes_map[i]
+            local = []
+            for j in range(1, len(merged_token)):
+                left = merged_token[:j]
+                right = merged_token[j:]
+                if (
+                    left in mergeable_ranks
+                    and right in mergeable_ranks
+                    and (left + right) in mergeable_ranks
+                ):
+                    local.append((left, right, i))
+            if not local:
+                raise ValueError(
+                    f"Could not find valid merge for token at rank {i}: {merged_token.decode('latin-1')}"
+                )
+            local = sorted(
+                local,
+                key=lambda x: (mergeable_ranks[x[0]], mergeable_ranks[x[1]]),
+                reverse=False,
+            )
+            merge_pairs.extend(local)
+        merge_pairs = sorted(merge_pairs, key=lambda val: val[2], reverse=False)
+
+        byte_encoder = bytes_to_unicode()
+
+        decoded_merge_pairs = [
+            [
+                self.token_bytes_to_string(val[0], byte_encoder),
+                self.token_bytes_to_string(val[1], byte_encoder),
+            ]
+            for val in merge_pairs
+        ]
+
+        merges = [
+            " ".join(
+                [
+                    # ensure the spaces are properly encoded
+                    "".join(chr(ord(c) + 256) if c == " " else c for c in part)
+                    for part in pair
+                ]
+            )
+            for pair in decoded_merge_pairs
+        ]
+
+        return merges

requirements/requirements-convert_hf_to_gguf.txt

@@ -1,3 +1,5 @@
+mistral-common>=1.8.3
+
 -r ./requirements-convert_legacy_llama.txt
 --extra-index-url https://download.pytorch.org/whl/cpu
 torch~=2.2.1; platform_machine != "s390x"

requirements/requirements-pydantic.txt

@@ -1,3 +1,3 @@
 docstring_parser~=0.15
-pydantic~=2.6.3
+pydantic~=2.11.7
 requests

tools/mtmd/clip-impl.h

@@ -131,6 +131,7 @@ enum projector_type {
     PROJECTOR_TYPE_LLAMA4,
     PROJECTOR_TYPE_QWEN2A,
     PROJECTOR_TYPE_QWEN25O, // will be replaced by QWEN2A or QWEN25VL depending on clip_ctx
+    PROJECTOR_TYPE_VOXTRAL,
     PROJECTOR_TYPE_UNKNOWN,
 };
 
@@ -150,6 +151,7 @@ static std::map<projector_type, std::string> PROJECTOR_TYPE_NAMES = {
     { PROJECTOR_TYPE_LLAMA4,    "llama4"},
     { PROJECTOR_TYPE_QWEN2A,    "qwen2a"},
     { PROJECTOR_TYPE_QWEN25O,   "qwen2.5o"},
+    { PROJECTOR_TYPE_VOXTRAL,   "voxtral"},
 };
 
 static projector_type clip_projector_type_from_string(const std::string & str) {

tools/mtmd/clip.cpp

@@ -354,6 +354,16 @@ struct clip_model {
     ggml_tensor * conv1d_2_b = nullptr;
     ggml_tensor * mm_norm_pre_w = nullptr;
     ggml_tensor * mm_norm_mid_w = nullptr;
+
+    bool audio_has_avgpool() const {
+        return proj_type == PROJECTOR_TYPE_QWEN2A
+            || proj_type == PROJECTOR_TYPE_VOXTRAL;
+    }
+
+    bool audio_has_stack_frames() const {
+        return proj_type == PROJECTOR_TYPE_ULTRAVOX
+            || proj_type == PROJECTOR_TYPE_VOXTRAL;
+    }
 };
 
 struct clip_ctx {
@@ -1483,49 +1493,52 @@ struct clip_graph {
 
         cb(cur, "after_transformer", -1);
 
-        if (ctx->proj_type() == PROJECTOR_TYPE_ULTRAVOX) {
+        if (model.audio_has_stack_frames()) {
             // StackAudioFrames
             // https://huggingface.co/fixie-ai/ultravox-v0_5-llama-3_2-1b/blob/main/ultravox_model.py
-            {
+            int64_t stride = n_embd * hparams.proj_stack_factor;
-                int64_t stride = n_embd * hparams.proj_stack_factor;
+            int64_t padded_len = GGML_PAD(ggml_nelements(cur), stride);
-                int64_t padded_len = GGML_PAD(ggml_nelements(cur), stride);
+            int64_t pad = padded_len - ggml_nelements(cur);
-                int64_t pad = padded_len - ggml_nelements(cur);
+            if (pad > 0) {
-                if (pad > 0) {
+                cur = ggml_view_1d(ctx0, cur, ggml_nelements(cur), 0);
-                    cur = ggml_view_1d(ctx0, cur, ggml_nelements(cur), 0);
+                cur = ggml_pad(ctx0, cur, pad, 0, 0, 0);
-                    cur = ggml_pad(ctx0, cur, pad, 0, 0, 0);
-                }
-                cur = ggml_view_2d(ctx0, cur, stride, padded_len / stride,
-                                    ggml_row_size(cur->type, stride), 0);
             }
-
+            cur = ggml_view_2d(ctx0, cur, stride, padded_len / stride,
+                                ggml_row_size(cur->type, stride), 0);
             cb(cur, "after_stacked", -1);
+        }
 
+        if (ctx->proj_type() == PROJECTOR_TYPE_ULTRAVOX) {
             // UltravoxProjector
-            {
+            // pre-norm
-                // pre-norm
+            cur = ggml_rms_norm(ctx0, cur, 1e-6);
-                cur = ggml_rms_norm(ctx0, cur, 1e-6);
+            cur = ggml_mul(ctx0, cur, model.mm_norm_pre_w);
-                cur = ggml_mul(ctx0, cur, model.mm_norm_pre_w);
 
-                // ffn in
+            // ffn in
-                cur = ggml_mul_mat(ctx0, model.mm_1_w, cur);
+            cur = ggml_mul_mat(ctx0, model.mm_1_w, cur);
 
-                // swiglu
+            // swiglu
-                // see SwiGLU in ultravox_model.py, the second half passed through is silu, not the first half
+            // see SwiGLU in ultravox_model.py, the second half passed through is silu, not the first half
-                cur = ggml_swiglu_swapped(ctx0, cur);
+            cur = ggml_swiglu_swapped(ctx0, cur);
 
-                // mid-norm
+            // mid-norm
-                cur = ggml_rms_norm(ctx0, cur, 1e-6);
+            cur = ggml_rms_norm(ctx0, cur, 1e-6);
-                cur = ggml_mul(ctx0, cur, model.mm_norm_mid_w);
+            cur = ggml_mul(ctx0, cur, model.mm_norm_mid_w);
 
-                // ffn out
+            // ffn out
-                cur = ggml_mul_mat(ctx0, model.mm_2_w, cur);
+            cur = ggml_mul_mat(ctx0, model.mm_2_w, cur);
-            }
 
         } else if (ctx->proj_type() == PROJECTOR_TYPE_QWEN2A) {
             // projector
             cur = ggml_mul_mat(ctx0, model.mm_fc_w, cur);
             cur = ggml_add(ctx0, cur, model.mm_fc_b);
 
+        } else if (ctx->proj_type() == PROJECTOR_TYPE_VOXTRAL) {
+            // projector
+            cur = ggml_mul_mat(ctx0, model.mm_1_w, cur);
+            cur = ggml_gelu_erf(ctx0, cur);
+            cur = ggml_mul_mat(ctx0, model.mm_2_w, cur);
+
         } else {
             GGML_ABORT("%s: unknown projector type", __func__);
         }
@@ -1670,8 +1683,7 @@ private:
             inpL = cur;
         }
 
-        // TODO @ngxson : find a way to move this outside
+        if (ctx->model.audio_has_avgpool()) {
-        if (ctx->proj_type() == PROJECTOR_TYPE_QWEN2A) {
             ggml_tensor * cur = inpL;
             cur = ggml_transpose(ctx0, cur);
             cur = ggml_cont(ctx0, cur);
@@ -1985,6 +1997,7 @@ static ggml_cgraph * clip_image_build_graph(clip_ctx * ctx, const clip_image_f32
                 res = graph.build_llama4();
             } break;
         case PROJECTOR_TYPE_ULTRAVOX:
+        case PROJECTOR_TYPE_VOXTRAL:
         case PROJECTOR_TYPE_QWEN2A:
             {
                 res = graph.build_whisper_enc();
@@ -2259,8 +2272,10 @@ struct clip_model_loader {
                     } break;
                 case PROJECTOR_TYPE_ULTRAVOX:
                 case PROJECTOR_TYPE_QWEN2A:
+                case PROJECTOR_TYPE_VOXTRAL:
                     {
-                        bool require_stack = model.proj_type == PROJECTOR_TYPE_ULTRAVOX;
+                        bool require_stack = model.proj_type == PROJECTOR_TYPE_ULTRAVOX ||
+                                             model.proj_type == PROJECTOR_TYPE_VOXTRAL;
                         get_u32(KEY_A_PROJ_STACK_FACTOR, hparams.proj_stack_factor, require_stack);
                         if (hparams.n_mel_bins != 128) {
                             throw std::runtime_error(string_format("%s: only 128 mel bins are supported for ultravox\n", __func__));
@@ -2544,6 +2559,15 @@ struct clip_model_loader {
                     model.mm_fc_w = get_tensor(string_format(TN_MM_AUDIO_FC, "weight"));
                     model.mm_fc_b = get_tensor(string_format(TN_MM_AUDIO_FC, "bias"));
                 } break;
+            case PROJECTOR_TYPE_VOXTRAL:
+                {
+                    model.conv1d_1_w = get_tensor(string_format(TN_CONV1D, 1, "weight"));
+                    model.conv1d_1_b = get_tensor(string_format(TN_CONV1D, 1, "bias"));
+                    model.conv1d_2_w = get_tensor(string_format(TN_CONV1D, 2, "weight"));
+                    model.conv1d_2_b = get_tensor(string_format(TN_CONV1D, 2, "bias"));
+                    model.mm_1_w = get_tensor(string_format(TN_MM_AUDIO_MLP, 1, "weight"));
+                    model.mm_2_w = get_tensor(string_format(TN_MM_AUDIO_MLP, 2, "weight"));
+                } break;
             case PROJECTOR_TYPE_INTERNVL:
                 {
                     model.mm_0_w = get_tensor(string_format(TN_MVLM_PROJ_MLP, 0, "weight"));
@@ -3570,17 +3594,26 @@ int clip_n_output_tokens(const struct clip_ctx * ctx, struct clip_image_f32 * im
                 int scale_factor = ctx->model.hparams.proj_scale_factor;
                 n_patches_sq /= (scale_factor * scale_factor);
             } break;
+        case PROJECTOR_TYPE_VOXTRAL:
         case PROJECTOR_TYPE_ULTRAVOX:
-            {
-                const int proj_stack_factor = ctx->model.hparams.proj_stack_factor;
-                const int n_len = CLIP_ALIGN(img->nx, proj_stack_factor);
-                n_patches_sq = n_len / proj_stack_factor / 2;
-            } break;
         case PROJECTOR_TYPE_QWEN2A:
             {
-                // divide by 2 because of whisper
+                n_patches_sq = img->nx;
-                // another divide by 2 because of nn.AvgPool1d(2, stride=2)
+
-                n_patches_sq = img->nx / 4;
+                const int proj_stack_factor = ctx->model.hparams.proj_stack_factor;
+                if (ctx->model.audio_has_stack_frames()) {
+                    GGML_ASSERT(proj_stack_factor > 0);
+                    const int n_len = CLIP_ALIGN(n_patches_sq, proj_stack_factor);
+                    n_patches_sq = n_len / proj_stack_factor;
+                }
+
+                // whisper downscales input token by half after conv1d
+                n_patches_sq /= 2;
+
+                if (ctx->model.audio_has_avgpool()) {
+                    // divide by 2 because of nn.AvgPool1d(2, stride=2)
+                    n_patches_sq /= 2;
+                }
             } break;
         default:
             GGML_ABORT("unsupported projector type");
@@ -3986,6 +4019,7 @@ bool clip_image_batch_encode(clip_ctx * ctx, const int n_threads, const clip_ima
         case PROJECTOR_TYPE_INTERNVL:
         case PROJECTOR_TYPE_QWEN2A:
         case PROJECTOR_TYPE_ULTRAVOX:
+        case PROJECTOR_TYPE_VOXTRAL:
             {
                 // do nothing
             } break;
@@ -4086,6 +4120,7 @@ int clip_n_mmproj_embd(const struct clip_ctx * ctx) {
         case PROJECTOR_TYPE_IDEFICS3:
             return ctx->model.projection->ne[1];
         case PROJECTOR_TYPE_ULTRAVOX:
+        case PROJECTOR_TYPE_VOXTRAL:
             return ctx->model.mm_2_w->ne[1];
         case PROJECTOR_TYPE_INTERNVL:
             return ctx->model.mm_3_w->ne[1];
@@ -4132,7 +4167,8 @@ bool clip_has_audio_encoder(const struct clip_ctx * ctx) {
 
 bool clip_has_whisper_encoder(const struct clip_ctx * ctx) {
     return ctx->proj_type() == PROJECTOR_TYPE_ULTRAVOX
-        || ctx->proj_type() == PROJECTOR_TYPE_QWEN2A;
+        || ctx->proj_type() == PROJECTOR_TYPE_QWEN2A
+        || ctx->proj_type() == PROJECTOR_TYPE_VOXTRAL;
 }
 
 bool clip_encode_float_image (struct clip_ctx * ctx, int n_threads, float * img, int h, int w, float * vec) {

tools/mtmd/mtmd.cpp

@@ -289,6 +289,10 @@ struct mtmd_context {
             aud_beg = "<|audio_bos|>";
             aud_end = "<|audio_eos|>";
 
+        } else if (proj == PROJECTOR_TYPE_ULTRAVOX) {
+            // [BEGIN_AUDIO] ... (embeddings) ...
+            aud_beg = "[BEGIN_AUDIO]";
+
         }
     }
 

tools/mtmd/requirements.txt

@@ -1,5 +1,5 @@
 -r ../../requirements/requirements-convert_legacy_llama.txt
 --extra-index-url https://download.pytorch.org/whl/cpu
-pillow~=10.2.0
+pillow~=11.3.0
 torch~=2.2.1
 torchvision~=0.17.1

tools/mtmd/tests.sh

@@ -71,6 +71,7 @@ add_test_vision "ggml-org/Qwen2.5-Omni-3B-GGUF:Q4_K_M"
 
 add_test_audio  "ggml-org/ultravox-v0_5-llama-3_2-1b-GGUF:Q8_0"
 add_test_audio  "ggml-org/Qwen2.5-Omni-3B-GGUF:Q4_K_M"
+add_test_audio  "ggml-org/Voxtral-Mini-3B-2507-GGUF:Q4_K_M"
 
 # to test the big models, run: ./tests.sh big
 if [ "$RUN_BIG_TESTS" = true ]; then