On 06/08/13 21:40, Christian Schmidt wrote:
> This patch removes the header decoding for PCM audio from
> libavformat/mpeg.c and the 20/24bit parts from libavcodec/pcm.c,
> and merges them into a new decoder in libavcodec/pcm-mpeg.c.
>
> The decoder has added support for samples that span multiple
> packets and modified 20/24bit group decoding. Both is needed to
> decode samples that have been generated with DVD-Lab Pro 2. The
> decoding of 16bit PCM and two channel 24bit is identical to
> before. No other samples are known to verify the correctness of
> the encoding this software does.
> The complete list of tested formats is
> 48kHz/16bit/2-8 channels
> 48kHz/24bit/2-5 channels
> 96kHz/16bit/2-4 channels
> 96kHz/24bit/2 channels
> ---
> More cosmetics.
>
> libavcodec/Makefile | 2 +-
> libavcodec/pcm-mpeg.c | 260
> ++++++++++++++++++++++++++++++++++++++++++++++++++
> libavcodec/pcm.c | 43 +--------
> libavformat/mpeg.c | 28 +-----
> 4 files changed, 263 insertions(+), 70 deletions(-)
>
> diff --git a/libavcodec/Makefile b/libavcodec/Makefile
> index 2ba1a32..f1475ef 100644
> --- a/libavcodec/Makefile
> +++ b/libavcodec/Makefile
> @@ -423,7 +423,7 @@ OBJS-$(CONFIG_ZMBV_ENCODER) += zmbvenc.o
> OBJS-$(CONFIG_PCM_ALAW_DECODER) += pcm.o
> OBJS-$(CONFIG_PCM_ALAW_ENCODER) += pcm.o
> OBJS-$(CONFIG_PCM_BLURAY_DECODER) += pcm-mpeg.o
> -OBJS-$(CONFIG_PCM_DVD_DECODER) += pcm.o
> +OBJS-$(CONFIG_PCM_DVD_DECODER) += pcm-mpeg.o
> OBJS-$(CONFIG_PCM_F32BE_DECODER) += pcm.o
> OBJS-$(CONFIG_PCM_F32BE_ENCODER) += pcm.o
> OBJS-$(CONFIG_PCM_F32LE_DECODER) += pcm.o
> diff --git a/libavcodec/pcm-mpeg.c b/libavcodec/pcm-mpeg.c
> index f28746d..bdbcd50 100644
> --- a/libavcodec/pcm-mpeg.c
> +++ b/libavcodec/pcm-mpeg.c
> @@ -29,6 +29,15 @@
> #include "bytestream.h"
> #include "internal.h"
>
> +typedef struct PCMDVDContext {
> + uint32_t last_header; // Cached header to see if parsing is needed
> + int block_size; // Size of a block of samples in bytes
> + int samples_per_block; // Number of samples per channel per block
> + int groups_per_block; // Number of 20/24bit sammple groups per block
typo.
> + uint8_t *extra_samples; // Pointer to leftover samples from a frame
> + int extra_sample_count; // Number of leftover samples in the buffer
> +} PCMDVDContext;
> +
> /*
> * Channel Mapping according to
> * Blu-ray Disc Read-Only Format Version 1
> @@ -302,6 +311,242 @@ static int pcm_bluray_decode_frame(AVCodecContext
> *avctx, void *data,
> return retval + 4;
> }
>
> +static av_cold int pcm_dvd_decode_init(AVCodecContext *avctx)
> +{
> + PCMDVDContext *s = avctx->priv_data;
> +
> + /* Invalid header to force parsing of the first header */
> + s->last_header = -1;
> + /* reserve space for 8 channels, 3 bytes/sample, 4 samples/block */
> + if (!(s->extra_samples = av_malloc(8 * 3 * 4)))
> + return AVERROR(ENOMEM);
> + s->extra_sample_count = 0;
> +
> + return 0;
> +}
> +
> +static av_cold int pcm_dvd_decode_uninit(AVCodecContext *avctx)
> +{
> + PCMDVDContext *s = avctx->priv_data;
> +
> + if (s->extra_samples)
> + av_free(s->extra_samples);
> +
> + return 0;
> +}
> +
> +static int pcm_dvd_parse_header(AVCodecContext *avctx, const uint8_t *header)
> +{
> + /* no traces of 44100 and 32000Hz in any commercial software or player */
> + static const uint32_t frequencies[4] = { 48000, 96000, 44100, 32000 };
> + PCMDVDContext *s = avctx->priv_data;
> + int header_int = (header[0] & 0xe0) | (header[1] << 8) | (header[2] <<
> 16);
> +
> + /* early exit if the header didn't change apart from the frame number */
> + if (s->last_header == header_int)
> + return 0;
> +
> + if (avctx->debug & FF_DEBUG_PICT_INFO)
> + av_dlog(avctx, "pcm_dvd_parse_header: header = %02x%02x%02x\n",
> + header[0], header[1], header[2]);
> + av_log(avctx, AV_LOG_INFO, "pcm_dvd_parse_header: header =
> %02x%02x%02x\n",
> + header[0], header[1], header[2]);
> + /*
> + * header[0] emphasis (1), muse(1), reserved(1), frame number(5)
> + * header[1] quant (2), freq(2), reserved(1), channels(3)
> + * header[2] dynamic range control (0x80 = off)
> + */
> +
> + /* get the sample depth and derive the sample format from it */
> + avctx->bits_per_coded_sample = 16 + (header[1] >> 6 & 3) * 4;
> + if (avctx->bits_per_coded_sample == 28) {
> + av_log(avctx, AV_LOG_ERROR, "PCM DVD unsupported sample depth\n");
> + return AVERROR_INVALIDDATA;
> + }
> + avctx->sample_fmt = avctx->bits_per_coded_sample == 16 ?
> AV_SAMPLE_FMT_S16
> + :
> AV_SAMPLE_FMT_S32;
> + avctx->bits_per_raw_sample = avctx->bits_per_coded_sample;
> +
> + /* get the sample rate */
> + avctx->sample_rate = frequencies[header[1] >> 4 & 3];
> +
> + /* get the number of channels */
> + avctx->channels = 1 + (header[1] & 7);
> + /* calculate the bitrate */
> + avctx->bit_rate = avctx->channels *
> + avctx->sample_rate *
> + avctx->bits_per_coded_sample;
> +
> + /* 4 samples form a group in 20/24bit PCM on DVD Video.
> + * A block is formed by the number of groups that are
> + * needed to complete a set of samples for each channel. */
> + if (avctx->bits_per_coded_sample == 16) {
> + s->samples_per_block = 1;
> + s->block_size = avctx->channels * 2;
> + } else {
> + switch (avctx->channels) {
> + case 1:
> + case 2:
> + case 4:
> + /* one group has all the samples needed */
> + s->block_size = 4 * avctx->bits_per_coded_sample / 8;
> + s->samples_per_block = 4 / avctx->channels;
> + s->groups_per_block = 1;
> + break;
> + case 8:
> + /* two groups have all the samples needed */
> + s->block_size = 8 * avctx->bits_per_coded_sample / 8;
> + s->samples_per_block = 1;
> + s->groups_per_block = 2;
> + break;
> + default:
> + /* need avctx->channels groups */
> + s->block_size = 4 * avctx->channels *
> + avctx->bits_per_coded_sample / 8;
> + s->samples_per_block = 4;
> + s->groups_per_block = avctx->channels;
> + break;
> + }
> + }
> +
> + if (avctx->debug & FF_DEBUG_PICT_INFO)
> + av_dlog(avctx,
> + "pcm_dvd_parse_header: %d channels, %d bits per sample, %d
> Hz, %d bit/s\n",
> + avctx->channels, avctx->bits_per_coded_sample,
> + avctx->sample_rate, avctx->bit_rate);
> +
> + s->last_header = header_int;
> +
> + return 0;
> +}
> +
> +static void *pcm_dvd_decode_samples(AVCodecContext *avctx, const uint8_t
> *src,
> + void *dst, int blocks)
> +{
> + PCMDVDContext *s = avctx->priv_data;
> + int16_t *dst16 = dst;
> + int32_t *dst32 = dst;
> + GetByteContext gb;
> + int i;
> + uint8_t t;
> + int samples;
> +
> + bytestream2_init(&gb, src, blocks * s->block_size);
> + switch (avctx->bits_per_coded_sample) {
> + case 16:
> +#if HAVE_BIGENDIAN
> + bytestream2_get_buffer(&gb, dst16, blocks * s->block_size);
> + dst16 += blocks * block_size / 2;
> +#else
> + samples = blocks * avctx->channels;
> + do {
> + *dst16++ = bytestream2_get_be16u(&gb);
> + } while (--samples);
> +#endif
> + return dst16;
> + case 20:
> + do {
> + for (i = s->groups_per_block; i; i--) {
> + dst32[0] = bytestream2_get_be16u(&gb) << 16;
> + dst32[1] = bytestream2_get_be16u(&gb) << 16;
> + dst32[2] = bytestream2_get_be16u(&gb) << 16;
> + dst32[3] = bytestream2_get_be16u(&gb) << 16;
> + t = bytestream2_get_byteu(&gb);
> + *dst32 += (t & 0xf0) << 8;
> + *dst32 += (t & 0x0f) << 12;
> + t = bytestream2_get_byteu(&gb);
> + *dst32 += (t & 0xf0) << 8;
> + *dst32 += (t & 0x0f) << 12;
> + }
> + } while (--blocks);
> + return dst32;
> + case 24:
> + do {
> + for (i = s->groups_per_block; i; i--) {
> + dst32[0] = bytestream2_get_be16u(&gb) << 16;
> + dst32[1] = bytestream2_get_be16u(&gb) << 16;
> + dst32[2] = bytestream2_get_be16u(&gb) << 16;
> + dst32[3] = bytestream2_get_be16u(&gb) << 16;
> + *dst32++ += bytestream2_get_byteu(&gb) << 8;
> + *dst32++ += bytestream2_get_byteu(&gb) << 8;
> + *dst32++ += bytestream2_get_byteu(&gb) << 8;
> + *dst32++ += bytestream2_get_byteu(&gb) << 8;
> + }
> + } while (--blocks);
> + return dst32;
> + default:
> + return NULL;
> + }
> +}
> +
> +static int pcm_dvd_decode_frame(AVCodecContext *avctx, void *data,
> + int *got_frame_ptr, AVPacket *avpkt)
> +{
> + AVFrame *frame = data;
> + const uint8_t *src = avpkt->data;
> + int buf_size = avpkt->size;
> + PCMDVDContext *s = avctx->priv_data;
> + int retval;
> + int blocks;
> + void *dst;
> +
> + if (buf_size < 3) {
> + av_log(avctx, AV_LOG_ERROR, "PCM packet too small\n");
> + return AVERROR_INVALIDDATA;
> + }
> +
> + if ((retval = pcm_dvd_parse_header(avctx, src)))
> + return retval;
> + src += 3;
> + buf_size -= 3;
> +
> + blocks = (buf_size + s->extra_sample_count) / s->block_size;
> +
> + /* get output buffer */
> + frame->nb_samples = blocks * s->samples_per_block;
> + if ((retval = ff_get_buffer(avctx, frame, 0)) < 0) {
> + av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
> + return retval;
> + }
> + dst = frame->data[0];
> +
> + /* consume leftover samples from last packet */
> + if (s->extra_sample_count) {
> + int missing_samples = s->block_size - s->extra_sample_count;
> + if (buf_size >= missing_samples) {
> + memcpy(s->extra_samples + s->extra_sample_count, src,
> + missing_samples);
> + dst = pcm_dvd_decode_samples(avctx, s->extra_samples, dst, 1);
> + src += missing_samples;
> + buf_size -= missing_samples;
> + s->extra_sample_count = 0;
> + blocks--;
> + } else {
> + /* new packet still doesn't have enough samples */
> + memcpy(s->extra_samples + s->extra_sample_count, src, buf_size);
> + s->extra_sample_count += buf_size;
> + return avpkt->size;
> + }
> + }
> +
> + /* decode remaining complete samples */
> + if (blocks) {
> + pcm_dvd_decode_samples(avctx, src, dst, blocks);
> + buf_size -= blocks * s->block_size;
> + }
> +
> + /* store leftover samples */
> + if (buf_size) {
> + src += blocks * s->block_size;
> + memcpy(s->extra_samples, src, buf_size);
> + s->extra_sample_count = buf_size;
> + }
> +
> + *got_frame_ptr = 1;
> +
> + return avpkt->size;
> +}
> +
> AVCodec ff_pcm_bluray_decoder = {
> .name = "pcm_bluray",
> .type = AVMEDIA_TYPE_AUDIO,
> @@ -313,3 +558,18 @@ AVCodec ff_pcm_bluray_decoder = {
> },
> .long_name = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit
> big-endian for Blu-ray media"),
> };
> +
> +AVCodec ff_pcm_dvd_decoder = {
> + .name = "pcm_dvd",
> + .long_name = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit
> big-endian for DVD media"),
> + .type = AVMEDIA_TYPE_AUDIO,
> + .id = AV_CODEC_ID_PCM_DVD,
> + .priv_data_size = sizeof(PCMDVDContext),
> + .init = pcm_dvd_decode_init,
> + .decode = pcm_dvd_decode_frame,
> + .close = pcm_dvd_decode_uninit,
> + .capabilities = CODEC_CAP_DR1,
> + .sample_fmts = (const enum AVSampleFormat[]) {
> + AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_NONE
> + }
> +};
> diff --git a/libavcodec/pcm.c b/libavcodec/pcm.c
> index 31ee283..5b3bdf4 100644
> --- a/libavcodec/pcm.c
> +++ b/libavcodec/pcm.c
> @@ -265,16 +265,7 @@ static int pcm_decode_frame(AVCodecContext *avctx, void
> *data,
>
> /* av_get_bits_per_sample returns 0 for AV_CODEC_ID_PCM_DVD */
> samples_per_block = 1;
> - if (avctx->codec->id == AV_CODEC_ID_PCM_DVD) {
> - if (avctx->bits_per_coded_sample != 20 &&
> - avctx->bits_per_coded_sample != 24) {
> - av_log(avctx, AV_LOG_ERROR, "PCM DVD unsupported sample
> depth\n");
> - return AVERROR(EINVAL);
> - }
> - /* 2 samples are interleaved per block in PCM_DVD */
> - samples_per_block = 2;
> - sample_size = avctx->bits_per_coded_sample * 2 / 8;
> - } else if (avctx->codec_id == AV_CODEC_ID_PCM_LXF) {
> + if (avctx->codec_id == AV_CODEC_ID_PCM_LXF) {
> /* we process 40-bit blocks per channel for LXF */
> samples_per_block = 2;
> sample_size = 5;
> @@ -408,37 +399,6 @@ static int pcm_decode_frame(AVCodecContext *avctx, void
> *data,
> samples += 2;
> }
> break;
> - case AV_CODEC_ID_PCM_DVD:
> - {
> - const uint8_t *src8;
> - dst_int32_t = (int32_t *)frame->data[0];
> - n /= avctx->channels;
> - switch (avctx->bits_per_coded_sample) {
> - case 20:
> - while (n--) {
> - c = avctx->channels;
> - src8 = src + 4 * c;
> - while (c--) {
> - *dst_int32_t++ = (bytestream_get_be16(&src) << 16) +
> ((*src8 & 0xf0) << 8);
> - *dst_int32_t++ = (bytestream_get_be16(&src) << 16) +
> ((*src8++ & 0x0f) << 12);
> - }
> - src = src8;
> - }
> - break;
> - case 24:
> - while (n--) {
> - c = avctx->channels;
> - src8 = src + 4 * c;
> - while (c--) {
> - *dst_int32_t++ = (bytestream_get_be16(&src) << 16) +
> ((*src8++) << 8);
> - *dst_int32_t++ = (bytestream_get_be16(&src) << 16) +
> ((*src8++) << 8);
> - }
> - src = src8;
> - }
> - break;
> - }
> - break;
> - }
> case AV_CODEC_ID_PCM_LXF:
> {
> int i;
> @@ -522,7 +482,6 @@ AVCodec ff_ ## name_ ## _decoder = {
> \
>
> /* Note: Do not forget to add new entries to the Makefile as well. */
> PCM_CODEC (PCM_ALAW, AV_SAMPLE_FMT_S16, pcm_alaw, "PCM
> A-law");
> -PCM_DECODER(PCM_DVD, AV_SAMPLE_FMT_S32, pcm_dvd, "PCM
> signed 20|24-bit big-endian");
> PCM_CODEC (PCM_F32BE, AV_SAMPLE_FMT_FLT, pcm_f32be, "PCM
> 32-bit floating point big-endian");
> PCM_CODEC (PCM_F32LE, AV_SAMPLE_FMT_FLT, pcm_f32le, "PCM
> 32-bit floating point little-endian");
> PCM_CODEC (PCM_F64BE, AV_SAMPLE_FMT_DBL, pcm_f64be, "PCM
> 64-bit floating point big-endian");
> diff --git a/libavformat/mpeg.c b/libavformat/mpeg.c
> index 8a4c6d7..7430bb0 100644
> --- a/libavformat/mpeg.c
> +++ b/libavformat/mpeg.c
> @@ -453,7 +453,6 @@ static int mpegps_read_packet(AVFormatContext *s,
> codec_id = AV_CODEC_ID_DTS;
> } else if (startcode >= 0xa0 && startcode <= 0xaf) {
> type = AVMEDIA_TYPE_AUDIO;
> - /* 16 bit form will be handled as AV_CODEC_ID_PCM_S16BE */
> codec_id = AV_CODEC_ID_PCM_DVD;
> } else if (startcode >= 0xb0 && startcode <= 0xbf) {
> type = AVMEDIA_TYPE_AUDIO;
> @@ -494,35 +493,10 @@ static int mpegps_read_packet(AVFormatContext *s,
> st->id = startcode;
> st->codec->codec_type = type;
> st->codec->codec_id = codec_id;
> - if (codec_id != AV_CODEC_ID_PCM_S16BE)
> - st->need_parsing = AVSTREAM_PARSE_FULL;
> + st->need_parsing = AVSTREAM_PARSE_FULL;
> found:
> if(st->discard >= AVDISCARD_ALL)
> goto skip;
> - if ((startcode >= 0xa0 && startcode <= 0xaf) ||
> - (startcode == 0x1bd && ((dvdaudio_substream_type & 0xe0) == 0xa0))) {
> - int b1, freq;
> -
> - /* for LPCM, we just skip the header and consider it is raw
> - audio data */
> - if (len <= 3)
> - goto skip;
> - avio_r8(s->pb); /* emphasis (1), muse(1), reserved(1), frame
> number(5) */
> - b1 = avio_r8(s->pb); /* quant (2), freq(2), reserved(1), channels(3)
> */
> - avio_r8(s->pb); /* dynamic range control (0x80 = off) */
> - len -= 3;
> - freq = (b1 >> 4) & 3;
> - st->codec->sample_rate = lpcm_freq_tab[freq];
> - st->codec->channels = 1 + (b1 & 7);
> - st->codec->bits_per_coded_sample = 16 + ((b1 >> 6) & 3) * 4;
> - st->codec->bit_rate = st->codec->channels *
> - st->codec->sample_rate *
> - st->codec->bits_per_coded_sample;
> - if (st->codec->bits_per_coded_sample == 16)
> - st->codec->codec_id = AV_CODEC_ID_PCM_S16BE;
> - else if (st->codec->bits_per_coded_sample == 28)
> - return AVERROR(EINVAL);
> - }
> ret = av_get_packet(s->pb, pkt, len);
> pkt->pts = pts;
> pkt->dts = dts;
>
Looks good to me but would be nice having two files and not perpetuate
the pcm exceptional situation =)
lu
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