Given that this is a correctness fix and has gone through a few
iterations of review, any objections to merging now and exploring
optimizations around the padding later?
On Sat, Apr 26, 2025 at 1:05 AM Emma Worley <e...@emma.gg> wrote:
>
> Improves compatibility with Resolume products by adding an additional
> hashtable for DXT color+LUT combinations, and padding the DXT texture
> dimensions to the next largest multiple of 16. Produces identical
> packets to Resolume Alley in manual tests.
>
> Signed-off-by: Emma Worley <e...@emma.gg>
> ---
> libavcodec/dxvenc.c | 131 +++++++++++++++++++++++-------------
> tests/ref/fate/dxv3enc-dxt1 | 2 +-
> 2 files changed, 86 insertions(+), 47 deletions(-)
>
> diff --git a/libavcodec/dxvenc.c b/libavcodec/dxvenc.c
> index 6eaf363f06..ee6a0a5b36 100644
> --- a/libavcodec/dxvenc.c
> +++ b/libavcodec/dxvenc.c
> @@ -34,6 +34,11 @@
>
> #define DXV_HEADER_LENGTH 12
>
> +/*
> + * Resolume will refuse to display frames that are not padded to 16x16
> pixels.
> + */
> +#define DXV_ALIGN(x) FFALIGN(x, 16)
> +
> /*
> * DXV uses LZ-like back-references to avoid copying words that have already
> * appeared in the decompressed stream. Using a simple hash table (HT)
> @@ -60,6 +65,7 @@ typedef struct DXVEncContext {
>
> FFHashtableContext *color_ht;
> FFHashtableContext *lut_ht;
> + FFHashtableContext *combo_ht;
> } DXVEncContext;
>
> /* Converts an index offset value to a 2-bit opcode and pushes it to a
> stream.
> @@ -94,10 +100,14 @@ static int dxv_compress_dxt1(AVCodecContext *avctx)
> DXVEncContext *ctx = avctx->priv_data;
> PutByteContext *pbc = &ctx->pbc;
> void *value;
> - uint32_t color, lut, idx, color_idx, lut_idx, prev_pos, state = 16, pos
> = 0, op = 0;
> + uint64_t combo;
> + uint32_t color, lut, idx, combo_idx, prev_pos, old_pos, state = 16, pos
> = 0, op = 0;
>
> ff_hashtable_clear(ctx->color_ht);
> ff_hashtable_clear(ctx->lut_ht);
> + ff_hashtable_clear(ctx->combo_ht);
> +
> + ff_hashtable_set(ctx->combo_ht, ctx->tex_data, &pos);
>
> bytestream2_put_le32(pbc, AV_RL32(ctx->tex_data));
> ff_hashtable_set(ctx->color_ht, ctx->tex_data, &pos);
> @@ -107,51 +117,46 @@ static int dxv_compress_dxt1(AVCodecContext *avctx)
> pos++;
>
> while (pos + 2 <= ctx->tex_size / 4) {
> - idx = 0;
> - color_idx = 0;
> - lut_idx = 0;
> + combo = AV_RL64(ctx->tex_data + pos * 4);
> + combo_idx = ff_hashtable_get(ctx->combo_ht, &combo, &prev_pos) ? pos
> - prev_pos : 0;
> + idx = combo_idx;
> + PUSH_OP(2);
> + if (pos >= LOOKBACK_WORDS) {
> + old_pos = pos - LOOKBACK_WORDS;
> + if (ff_hashtable_get(ctx->combo_ht, ctx->tex_data + old_pos * 4,
> &prev_pos) && prev_pos <= old_pos)
> + ff_hashtable_delete(ctx->combo_ht, ctx->tex_data + old_pos *
> 4);
> + }
> + ff_hashtable_set(ctx->combo_ht, &combo, &pos);
>
> color = AV_RL32(ctx->tex_data + pos * 4);
> - if (ff_hashtable_get(ctx->color_ht, &color, &prev_pos))
> - color_idx = pos - prev_pos;
> - ff_hashtable_set(ctx->color_ht, &color, &pos);
> -
> + if (!combo_idx) {
> + idx = ff_hashtable_get(ctx->color_ht, &color, &prev_pos) ? pos -
> prev_pos : 0;
> + PUSH_OP(2);
> + if (!idx)
> + bytestream2_put_le32(pbc, color);
> + }
> if (pos >= LOOKBACK_WORDS) {
> - uint32_t old_pos = pos - LOOKBACK_WORDS;
> + old_pos = pos - LOOKBACK_WORDS;
> if (ff_hashtable_get(ctx->color_ht, ctx->tex_data + old_pos * 4,
> &prev_pos) && prev_pos <= old_pos)
> ff_hashtable_delete(ctx->color_ht, ctx->tex_data + old_pos *
> 4);
> }
> + ff_hashtable_set(ctx->color_ht, &color, &pos);
> pos++;
>
> lut = AV_RL32(ctx->tex_data + pos * 4);
> - if (color_idx && lut == AV_RL32(ctx->tex_data + (pos - color_idx) *
> 4)) {
> - idx = color_idx;
> - } else {
> - idx = 0;
> - if (ff_hashtable_get(ctx->lut_ht, &lut, &prev_pos))
> - lut_idx = pos - prev_pos;
> - ff_hashtable_set(ctx->lut_ht, &lut, &pos);
> + if (!combo_idx) {
> + idx = ff_hashtable_get(ctx->lut_ht, &lut, &prev_pos) ? pos -
> prev_pos : 0;
> + PUSH_OP(2);
> + if (!idx)
> + bytestream2_put_le32(pbc, lut);
> }
> if (pos >= LOOKBACK_WORDS) {
> - uint32_t old_pos = pos - LOOKBACK_WORDS;
> + old_pos = pos - LOOKBACK_WORDS;
> if (ff_hashtable_get(ctx->lut_ht, ctx->tex_data + old_pos * 4,
> &prev_pos) && prev_pos <= old_pos)
> ff_hashtable_delete(ctx->lut_ht, ctx->tex_data + old_pos *
> 4);
> }
> + ff_hashtable_set(ctx->lut_ht, &lut, &pos);
> pos++;
> -
> - PUSH_OP(2);
> -
> - if (!idx) {
> - idx = color_idx;
> - PUSH_OP(2);
> - if (!idx)
> - bytestream2_put_le32(pbc, color);
> -
> - idx = lut_idx;
> - PUSH_OP(2);
> - if (!idx)
> - bytestream2_put_le32(pbc, lut);
> - }
> }
>
> return 0;
> @@ -172,12 +177,50 @@ static int dxv_encode(AVCodecContext *avctx, AVPacket
> *pkt,
> return ret;
>
> if (ctx->enc.tex_funct) {
> + uint8_t *safe_data[4] = {frame->data[0], 0, 0, 0};
> + int safe_linesize[4] = {frame->linesize[0], 0, 0, 0};
> +
> + if (avctx->width != DXV_ALIGN(avctx->width) || avctx->height !=
> DXV_ALIGN(avctx->height)) {
> + ret = av_image_alloc(
> + safe_data,
> + safe_linesize,
> + DXV_ALIGN(avctx->width),
> + DXV_ALIGN(avctx->height),
> + avctx->pix_fmt,
> + 1);
> + if (ret < 0)
> + return ret;
> +
> + av_image_copy2(
> + safe_data,
> + safe_linesize,
> + frame->data,
> + frame->linesize,
> + avctx->pix_fmt,
> + avctx->width,
> + avctx->height);
> +
> + if (avctx->width != DXV_ALIGN(avctx->width)) {
> + for (int y = 0; y < avctx->height; y++) {
> + memset(safe_data[0] + y * safe_linesize[0] +
> frame->linesize[0], 0, safe_linesize[0] - frame->linesize[0]);
> + }
> + }
> + if (avctx->height != DXV_ALIGN(avctx->height)) {
> + for (int y = avctx->height; y < DXV_ALIGN(avctx->height);
> y++) {
> + memset(safe_data[0] + y * safe_linesize[0], 0,
> safe_linesize[0]);
> + }
> + }
> + }
> +
> ctx->enc.tex_data.out = ctx->tex_data;
> - ctx->enc.frame_data.in = frame->data[0];
> - ctx->enc.stride = frame->linesize[0];
> - ctx->enc.width = avctx->width;
> - ctx->enc.height = avctx->height;
> + ctx->enc.frame_data.in = safe_data[0];
> + ctx->enc.stride = safe_linesize[0];
> + ctx->enc.width = DXV_ALIGN(avctx->width);
> + ctx->enc.height = DXV_ALIGN(avctx->height);
> ff_texturedsp_exec_compress_threads(avctx, &ctx->enc);
> +
> + if (safe_data[0] != frame->data[0])
> + av_freep(&safe_data[0]);
> } else {
> /* unimplemented: YCoCg formats */
> return AVERROR_INVALIDDATA;
> @@ -216,14 +259,6 @@ static av_cold int dxv_init(AVCodecContext *avctx)
> return ret;
> }
>
> - if (avctx->width % TEXTURE_BLOCK_W || avctx->height % TEXTURE_BLOCK_H) {
> - av_log(avctx,
> - AV_LOG_ERROR,
> - "Video size %dx%d is not multiple of
> "AV_STRINGIFY(TEXTURE_BLOCK_W)"x"AV_STRINGIFY(TEXTURE_BLOCK_H)".\n",
> - avctx->width, avctx->height);
> - return AVERROR_INVALIDDATA;
> - }
> -
> ff_texturedspenc_init(&texdsp);
>
> switch (ctx->tex_fmt) {
> @@ -237,10 +272,10 @@ static av_cold int dxv_init(AVCodecContext *avctx)
> return AVERROR_INVALIDDATA;
> }
> ctx->enc.raw_ratio = 16;
> - ctx->tex_size = avctx->width / TEXTURE_BLOCK_W *
> - avctx->height / TEXTURE_BLOCK_H *
> + ctx->tex_size = DXV_ALIGN(avctx->width) / TEXTURE_BLOCK_W *
> + DXV_ALIGN(avctx->height) / TEXTURE_BLOCK_H *
> ctx->enc.tex_ratio;
> - ctx->enc.slice_count = av_clip(avctx->thread_count, 1, avctx->height /
> TEXTURE_BLOCK_H);
> + ctx->enc.slice_count = av_clip(avctx->thread_count, 1,
> DXV_ALIGN(avctx->height) / TEXTURE_BLOCK_H);
>
> ctx->tex_data = av_malloc(ctx->tex_size);
> if (!ctx->tex_data) {
> @@ -251,6 +286,9 @@ static av_cold int dxv_init(AVCodecContext *avctx)
> if (ret < 0)
> return ret;
> ret = ff_hashtable_alloc(&ctx->lut_ht, sizeof(uint32_t),
> sizeof(uint32_t), LOOKBACK_HT_ELEMS);
> + if (ret < 0)
> + return ret;
> + ret = ff_hashtable_alloc(&ctx->combo_ht, sizeof(uint64_t),
> sizeof(uint32_t), LOOKBACK_HT_ELEMS);
> if (ret < 0)
> return ret;
>
> @@ -265,6 +303,7 @@ static av_cold int dxv_close(AVCodecContext *avctx)
>
> ff_hashtable_freep(&ctx->color_ht);
> ff_hashtable_freep(&ctx->lut_ht);
> + ff_hashtable_freep(&ctx->combo_ht);
>
> return 0;
> }
> diff --git a/tests/ref/fate/dxv3enc-dxt1 b/tests/ref/fate/dxv3enc-dxt1
> index 74849a8031..e09000e181 100644
> --- a/tests/ref/fate/dxv3enc-dxt1
> +++ b/tests/ref/fate/dxv3enc-dxt1
> @@ -3,4 +3,4 @@
> #codec_id 0: dxv
> #dimensions 0: 1920x1080
> #sar 0: 1/1
> -0, 0, 0, 1, 76521, 0xed387a5e
> +0, 0, 0, 1, 76190, 0x0e6f0326
> --
> 2.48.0
>
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