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• avutil : Fix linking x86 asm constants with Clang in MSVC mode

  12 juin, par Martin Storsjö

  avutil : Fix linking x86 asm constants with Clang in MSVC mode
  This fixes building with Clang in MSVC mode, for x86, which was
  
  broken in 6e49b8699657b808b7dc80033f2c3f2d0e029fa3 (in Nov 2024) ;
  
  previously it failed with undefined symbols for the constants
  
  defined with DECLARE_ASM_CONST, accessed via inline assembly.
  Before 57861911a34e1c33796be97f2b2f44e05fffd647, there was an
  
      #elif defined(__GNUC__) || defined(__clang__)
  
  case before the
  
      #elif defined(_MSC_VER)
  
  case for defining DECLARE_ASM_CONST, which included av_used.
  
  (This case included the explicit "defined(__clang__)" since
  
  f637046d3134a331e4b5a7243ac3dfb92735b8a5.)
  After 57861911a34e1c33796be97f2b2f44e05fffd647, it used the
  
  generic definition of DECLARE_ASM_CONST that also included
  
  av_used - which also worked for Clang in MSVC mode. But after
  
  6e49b8699657b808b7dc80033f2c3f2d0e029fa3, Clang in MSVC mode
  
  ended up using the MSVC specific variant which lacked the
  
  av_used declaration, causing linker errors due to undefined
  
  symbols.
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] libavutil/mem_internal.h

• FFMPEG C++/Kotlin Encode data from ByteArray (ByteBuffer) to subtitles and mux it with video

  21 août 2024, par Алексей Красноноженко

  I need to mux some byte data encoded to base64 String to mpeg-ts container. Can't find any solution to somehow encode this data to AVPacket. Using of "avcodec_encode_subtitle" supposes to have AVSubtitle with proper data. But how can I create/allocate AVSubtitle with my data ?

  


  Upd. The only variant I managed to create (in Kotlin, as my app is KMP) is that, but it gives error "Invalid data found when processing input" when encoding

  


  val data = AVSubtitleRect()&#xA;data.type(SUBTITLE_ASS)&#xA;data.ass(BytePointer(buffer))&#xA;val subtitle = AVSubtitle()&#xA;val pointerPointer = PointerPointer<avsubtitlerect>(1)&#xA;pointerPointer.put(data)&#xA;subtitle.rects(pointerPointer)&#xA;subtitle.pts(packet.pts())&#xA;&#xA;val bufferSize = 1024 * 1024&#xA;val encodedBuffer = BytePointer(av_malloc(bufferSize.toLong()))&#xA;&#xA;val result = avcodec_encode_subtitle(subtitleContext, encodedBuffer, bufferSize, subtitle)&#xA;&#xA;if (result >= 0) {&#xA;    val outSubtitlePacket = AVPacket()&#xA;    outSubtitlePacket.apply {&#xA;        data(encodedBuffer)&#xA;        outSubtitlePacket.size(result)&#xA;        outSubtitlePacket.stream_index(subtitleStreamIndex)&#xA;        duration(packet.duration())&#xA;        dts(packet.dts())&#xA;        pts(packet.pts())&#xA;        pos(packet.pos())&#xA;    }&#xA;&#xA;    av_interleaved_write_frame(avOutputCtx, outSubtitlePacket)&#xA;&#xA;    av_packet_unref(outSubtitlePacket)&#xA;    av_free(encodedBuffer)&#xA;}&#xA;</avsubtitlerect>

  


  C equivalent

  


  // Allocate the subtitle rect
AVSubtitleRect *data = av_mallocz(sizeof(AVSubtitleRect));
if (!data) {
    fprintf(stderr, "Could not allocate AVSubtitleRect.\n");
    return AVERROR(ENOMEM);
}
data->type = SUBTITLE_ASS;
data->ass = av_strdup(buffer);
if (!data->ass) {
    fprintf(stderr, "Could not allocate ASS buffer.\n");
    av_free(data);
    return AVERROR(ENOMEM);
}

// Allocate the subtitle
AVSubtitle subtitle;
memset(&subtitle, 0, sizeof(subtitle));
subtitle.rects = av_mallocz(sizeof(*subtitle.rects));
if (!subtitle.rects) {
    fprintf(stderr, "Could not allocate AVSubtitle rects.\n");
    av_free(data->ass);
    av_free(data);
    return AVERROR(ENOMEM);
}
subtitle.rects[0] = data;
subtitle.num_rects = 1;
subtitle.pts = packet->pts;

// Allocate buffer for encoded subtitle
int bufferSize = 1024 * 1024;
uint8_t *encodedBuffer = av_malloc(bufferSize);
if (!encodedBuffer) {
    fprintf(stderr, "Could not allocate buffer for encoded subtitle.\n");
    av_free(subtitle.rects);
    av_free(data->ass);
    av_free(data);
    return AVERROR(ENOMEM);
}

// Encode the subtitle
int result = avcodec_encode_subtitle(subtitleContext, encodedBuffer, bufferSize, &subtitle);
if (result >= 0) {
    // Create the output subtitle packet
    AVPacket outSubtitlePacket;
    av_init_packet(&outSubtitlePacket);
    outSubtitlePacket.data = encodedBuffer;
    outSubtitlePacket.size = result;
    outSubtitlePacket.stream_index = subtitleStreamIndex;
    outSubtitlePacket.duration = packet->duration;
    outSubtitlePacket.dts = packet->dts;
    outSubtitlePacket.pts = packet->pts;
    outSubtitlePacket.pos = packet->pos;

    // Write the subtitle packet
    result = av_interleaved_write_frame(avOutputCtx, &outSubtitlePacket);
    if (result < 0) {
        fprintf(stderr, "Error while writing subtitle packet: %s\n", av_err2str(result));
    }

    av_packet_unref(&outSubtitlePacket);
    av_free(encodedBuffer);
} else {
    fprintf(stderr, "Failed to encode subtitles. Reason: %s\n", av_err2str(result));
    av_free(encodedBuffer);
}

av_free(subtitle.rects);
av_free(data->ass);
av_free(data);


  


• lavc/h264dsp : R-V V high-depth h264_idct8_add

  11 juillet 2024, par Rémi Denis-Courmont

  lavc/h264dsp : R-V V high-depth h264_idct8_add
  Unlike the 8-bit version, we need two iterations to process this within
  
  128-bit vectors. This adds some extra complexity for pointer arithmetic
  
  and counting down which is unnecessary in the 8-bit variant.
  Accordingly the gain relative to C are just slight better than half as
  
  good with 128-bit vectors as with 256-bit ones.
  T-Head C908 (2 iterations) :
  
  h264_idct8_add_9bpp_c :       17.5
  
  h264_idct8_add_9bpp_rvv_i32 : 10.0
  
  h264_idct8_add_10bpp_c :      17.5
  
  h264_idct8_add_10bpp_rvv_i32 : 9.7
  
  h264_idct8_add_12bpp_c :      17.7
  
  h264_idct8_add_12bpp_rvv_i32 : 9.7
  
  h264_idct8_add_14bpp_c :      17.7
  
  h264_idct8_add_14bpp_rvv_i32 : 9.7
  SpacemiT X60 (single iteration) :
  
  h264_idct8_add_9bpp_c :       15.2
  
  h264_idct8_add_9bpp_rvv_i32 :  5.0
  
  h264_idct8_add_10bpp_c :      15.2
  
  h264_idct8_add_10bpp_rvv_i32 : 5.0
  
  h264_idct8_add_12bpp_c :      14.7
  
  h264_idct8_add_12bpp_rvv_i32 : 5.0
  
  h264_idct8_add_14bpp_c :      14.7
  
  h264_idct8_add_14bpp_rvv_i32 : 4.7
  

  • [DH] libavcodec/riscv/h264dsp_init.c
  • [DH] libavcodec/riscv/h264idct_rvv.S