[FFmpeg-devel] [PATCH 2/2] avcodec/apedec: Implement interim mode detection
Paul B Mahol
onemda at gmail.com
Sat Aug 26 20:29:40 EEST 2023
On Sat, Aug 26, 2023 at 6:54 PM Michael Niedermayer <michael at niedermayer.cc>
wrote:
> Fixes: NoLegacy.ape
> Found-by: Matt Ashland <mail at monkeysaudio.com>
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
> libavcodec/apedec.c | 106 +++++++++++++++++++++++++++++++++++---------
> 1 file changed, 84 insertions(+), 22 deletions(-)
>
> diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c
> index 8bd625ca05..249fc22e24 100644
> --- a/libavcodec/apedec.c
> +++ b/libavcodec/apedec.c
> @@ -171,6 +171,9 @@ typedef struct APEContext {
> int32_t *decoded_buffer;
> int decoded_size;
> int32_t *decoded[MAX_CHANNELS]; ///< decoded data for each
> channel
> + int32_t *interim_buffer;
> + int interim_size;
> + int32_t *interim[MAX_CHANNELS]; ///< decoded data for each
> channel
> int blocks_per_loop; ///< maximum number of
> samples to decode for each call
>
> int16_t* filterbuf[APE_FILTER_LEVELS]; ///< filter memory
> @@ -187,6 +190,7 @@ typedef struct APEContext {
> const uint8_t *ptr; ///< current position in
> frame data
>
> int error;
> + int interim_mode;
>
> void (*entropy_decode_mono)(struct APEContext *ctx, int
> blockstodecode);
> void (*entropy_decode_stereo)(struct APEContext *ctx, int
> blockstodecode);
> @@ -223,6 +227,7 @@ static av_cold int ape_decode_close(AVCodecContext
> *avctx)
> av_freep(&s->filterbuf[i]);
>
> av_freep(&s->decoded_buffer);
> + av_freep(&s->interim_buffer);
> av_freep(&s->data);
> s->decoded_size = s->data_size = 0;
>
> @@ -248,12 +253,15 @@ static av_cold int ape_decode_init(AVCodecContext
> *avctx)
> switch (s->bps) {
> case 8:
> avctx->sample_fmt = AV_SAMPLE_FMT_U8P;
> + s->interim_mode = 0;
> break;
> case 16:
> avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
> + s->interim_mode = 0;
> break;
> case 24:
> avctx->sample_fmt = AV_SAMPLE_FMT_S32P;
> + s->interim_mode = -1;
> break;
> default:
> avpriv_request_sample(avctx,
> @@ -1181,7 +1189,7 @@ static av_always_inline int
> predictor_update_filter(APEPredictor64 *p,
> const int decoded,
> const int filter,
> const int delayA,
> const int delayB,
> const int adaptA,
> const int adaptB,
> - int compression_level)
> + int interim_mode)
> {
> int64_t predictionA, predictionB;
> int32_t sign;
> @@ -1209,7 +1217,7 @@ static av_always_inline int
> predictor_update_filter(APEPredictor64 *p,
> p->buf[delayB - 3] * p->coeffsB[filter][3] +
> p->buf[delayB - 4] * p->coeffsB[filter][4];
>
> - if (compression_level < COMPRESSION_LEVEL_INSANE) {
> + if (interim_mode < 1) {
> predictionA = (int32_t)predictionA;
> predictionB = (int32_t)predictionB;
> p->lastA[filter] = decoded + ((int32_t)(predictionA +
> (predictionB >> 1)) >> 10);
> @@ -1234,33 +1242,74 @@ static av_always_inline int
> predictor_update_filter(APEPredictor64 *p,
>
> static void predictor_decode_stereo_3950(APEContext *ctx, int count)
> {
> - APEPredictor64 *p = &ctx->predictor64;
> - int32_t *decoded0 = ctx->decoded[0];
> - int32_t *decoded1 = ctx->decoded[1];
> + APEPredictor64 *p_default = &ctx->predictor64;
> + APEPredictor64 p_interim;
> + int lcount = count;
> + int num_passes = 1;
>
> ape_apply_filters(ctx, ctx->decoded[0], ctx->decoded[1], count);
> + if (ctx->interim_mode == -1) {
> + p_interim = *p_default;
> + num_passes ++;
> + memcpy(ctx->interim[0], ctx->decoded[0],
> sizeof(*ctx->interim[0])*count);
> + memcpy(ctx->interim[1], ctx->decoded[1],
> sizeof(*ctx->interim[1])*count);
> + }
>
> - while (count--) {
> - /* Predictor Y */
> - *decoded0 = predictor_update_filter(p, *decoded0, 0, YDELAYA,
> YDELAYB,
> - YADAPTCOEFFSA, YADAPTCOEFFSB,
> - ctx->compression_level);
> - decoded0++;
> - *decoded1 = predictor_update_filter(p, *decoded1, 1, XDELAYA,
> XDELAYB,
> - XADAPTCOEFFSA, XADAPTCOEFFSB,
> - ctx->compression_level);
> - decoded1++;
> + for(int pass = 0; pass < num_passes; pass++) {
>
Please fix your style in patches.
> + int32_t *decoded0, *decoded1;
> + int interim_mode = ctx->interim_mode > 0 || pass;
> + APEPredictor64 *p;
>
> - /* Combined */
> - p->buf++;
> + if (pass) {
> + p = &p_interim;
> + decoded0 = ctx->interim[0];
> + decoded1 = ctx->interim[1];
> + } else {
> + p = p_default;
> + decoded0 = ctx->decoded[0];
> + decoded1 = ctx->decoded[1];
> + }
> + p->buf = p->historybuffer;
> +
> + count = lcount;
> + while (count--) {
> + /* Predictor Y */
> + int32_t a0 = predictor_update_filter(p, *decoded0, 0,
> YDELAYA, YDELAYB,
> + YADAPTCOEFFSA,
> YADAPTCOEFFSB,
> + interim_mode);
> + int32_t a1 = predictor_update_filter(p, *decoded1, 1,
> XDELAYA, XDELAYB,
> + XADAPTCOEFFSA,
> XADAPTCOEFFSB,
> + interim_mode);
> + *decoded0++ = a0;
> + *decoded1++ = a1;
> + if (num_passes > 1) {
> + int32_t left = a1 - (unsigned)(a0 / 2);
> + int32_t right = left + a0;
> +
> + if (FFMAX(FFABS(left), FFABS(right)) > (1<<23)) {
> + ctx->interim_mode = !interim_mode;
> + av_log(ctx->avctx, AV_LOG_VERBOSE, "Interim mode:
> %d\n", ctx->interim_mode);
> + break;
> + }
> + }
>
> - /* Have we filled the history buffer? */
> - if (p->buf == p->historybuffer + HISTORY_SIZE) {
> - memmove(p->historybuffer, p->buf,
> - PREDICTOR_SIZE * sizeof(*p->historybuffer));
> - p->buf = p->historybuffer;
> + /* Combined */
> + p->buf++;
> +
> + /* Have we filled the history buffer? */
> + if (p->buf == p->historybuffer + HISTORY_SIZE) {
> + memmove(p->historybuffer, p->buf,
> + PREDICTOR_SIZE * sizeof(*p->historybuffer));
> + p->buf = p->historybuffer;
> + }
> }
> }
> + if (num_passes > 1 && ctx->interim_mode > 0) {
> + memcpy(ctx->decoded[0], ctx->interim[0],
> sizeof(*ctx->interim[0])*lcount);
> + memcpy(ctx->decoded[1], ctx->interim[1],
> sizeof(*ctx->interim[1])*lcount);
> + *p_default = p_interim;
> + p_default->buf = p_default->historybuffer;
> + }
> }
>
> static void predictor_decode_mono_3950(APEContext *ctx, int count)
> @@ -1590,6 +1639,19 @@ static int ape_decode_frame(AVCodecContext *avctx,
> AVFrame *frame,
> s->decoded[0] = s->decoded_buffer;
> s->decoded[1] = s->decoded_buffer + FFALIGN(blockstodecode, 8);
>
> + if (s->interim_mode < 0) {
> + av_fast_malloc(&s->interim_buffer, &s->interim_size,
> decoded_buffer_size);
> + if (!s->interim_buffer)
> + return AVERROR(ENOMEM);
> + memset(s->interim_buffer, 0, decoded_buffer_size);
> + s->interim[0] = s->interim_buffer;
> + s->interim[1] = s->interim_buffer + FFALIGN(blockstodecode, 8);
> + } else {
> + av_freep(&s->interim_buffer);
> + s->interim_size = 0;
> + memset(s->interim, 0, sizeof(s->interim));
> + }
> +
> s->error=0;
>
> if ((s->channels == 1) || (s->frameflags &
> APE_FRAMECODE_PSEUDO_STEREO))
> --
> 2.17.1
>
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