ffmpeg高版本重采样的pascal翻译

scc__ · 发表于 2015-2-5 19:22

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c语言的版本到处都有，pascal的不好找，只能自己翻译。

//use it like:
//AudioResampling(aCodecCtx, frame, AV_SAMPLE_FMT_S16, frame.channels, frame.sample_rate, audio_buf0);
function AudioResampling(audio_dec_ctx: PAVCodecContext; pAudioDecodeFrame: pAVFrame;
out_sample_fmt: TAVSampleFormat; out_channels: integer; out_sample_rate: integer; out_buf: pbyte): integer;
var
swr_ctx: pSwrContext = nil;
data_size: integer = 0;
ret: integer = 0;
src_ch_layout: int64;
dst_ch_layout: int64;
dst_nb_channels: integer = 0;
dst_linesize: integer = 0;
src_nb_samples: integer = 0;
dst_nb_samples: integer = 0;
max_dst_nb_samples: integer = 0;
dst_data: ppbyte = nil;
resampled_data_size: integer = 0;
begin
Result := -1;
src_ch_layout := audio_dec_ctx.channel_layout;
dst_ch_layout := AV_CH_LAYOUT_STEREO;
swr_ctx := swr_alloc();
if swr_ctx = nil then
begin
consolelog('swr_alloc error');
exit;
end;
if audio_dec_ctx.channels = av_get_channel_layout_nb_channels(audio_dec_ctx.channel_layout) then
src_ch_layout := audio_dec_ctx.channel_layout
else
src_ch_layout := av_get_default_channel_layout(audio_dec_ctx.channels);
if out_channels = 1 then
begin
dst_ch_layout := AV_CH_LAYOUT_MONO;
//consolelog('dst_ch_layout: AV_CH_LAYOUT_MONO');
end
else if out_channels = 2 then
begin
dst_ch_layout := AV_CH_LAYOUT_STEREO;
//consolelog('dst_ch_layout: AV_CH_LAYOUT_STEREO');
end
else
begin
dst_ch_layout := AV_CH_LAYOUT_SURROUND;
//consolelog('dst_ch_layout: AV_CH_LAYOUT_SURROUND');
end;
if src_ch_layout <= 0 then
begin
consolelog('src_ch_layout error');
exit;
end;
src_nb_samples := pAudioDecodeFrame.nb_samples;
if src_nb_samples <= 0 then
begin
consolelog('src_nb_samples error');
exit;
end;
av_opt_set_int(swr_ctx, 'in_channel_layout', src_ch_layout, 0);
av_opt_set_int(swr_ctx, 'in_sample_rate', audio_dec_ctx.sample_rate, 0);
av_opt_set_sample_fmt(swr_ctx, 'in_sample_fmt', audio_dec_ctx.sample_fmt, 0);
av_opt_set_int(swr_ctx, 'out_channel_layout', dst_ch_layout, 0);
av_opt_set_int(swr_ctx, 'out_sample_rate', out_sample_rate, 0);
av_opt_set_sample_fmt(swr_ctx, 'out_sample_fmt', out_sample_fmt, 0);
if swr_init(swr_ctx) < 0 then
begin
consolelog('Failed to initialize the resampling context');
exit;
end;
dst_nb_samples := av_rescale_rnd(src_nb_samples, out_sample_rate, audio_dec_ctx.sample_rate, AV_ROUND_UP);
max_dst_nb_samples := dst_nb_samples;
if max_dst_nb_samples <= 0 then
begin
consolelog('av_rescale_rnd error');
exit;
end;
dst_nb_channels := av_get_channel_layout_nb_channels(dst_ch_layout);
ret := av_samples_alloc_array_and_samples(@dst_data, @dst_linesize, dst_nb_channels,
dst_nb_samples, out_sample_fmt, 0);
if ret < 0 then
begin
consolelog('av_samples_alloc_array_and_samples error');
exit;
end;
dst_nb_samples := av_rescale_rnd(swr_get_delay(swr_ctx, audio_dec_ctx.sample_rate) +
src_nb_samples, out_sample_rate, audio_dec_ctx.sample_rate, AV_ROUND_UP);
if dst_nb_samples <= 0 then
begin
consolelog('av_rescale_rnd error ');
exit;
end;
if dst_nb_samples > max_dst_nb_samples then
begin
av_free(dst_data^);
ret := av_samples_alloc(dst_data, @dst_linesize, dst_nb_channels, dst_nb_samples,
out_sample_fmt, 1);
max_dst_nb_samples := dst_nb_samples;
end;
if swr_ctx <> nil then
begin
ret := swr_convert(swr_ctx, dst_data, dst_nb_samples, pAudioDecodeFrame.Data, pAudioDecodeFrame.nb_samples);
if (ret < 0) then
begin
consolelog('swr_convert error');
exit;
end;
resampled_data_size := av_samples_get_buffer_size(@dst_linesize, dst_nb_channels, ret,
out_sample_fmt, 1);
if (resampled_data_size < 0) then
begin
consolelog('av_samples_get_buffer_size error');
exit;
end;
end
else
begin
consolelog('swr_ctx null error');
exit;
end;
move(dst_data^^, out_buf^, resampled_data_size);
if (dst_data <> nil) then
begin
av_freep(@dst_data^);
end;
av_freep(@dst_data);
dst_data := nil;
if swr_ctx <> nil then
begin
swr_free(@swr_ctx);
end;
Result := resampled_data_size;
end;

复制代码

yeabilo · 发表于 2015-6-19 09:13

不了解不懂:(

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